LIGNOPHYTA

True roots +; lateral meristems: cork cambium producing cork abaxially, vascular cambium producing phloem abaxially and xylem adaxially.

EXTANT SEED PLANTS/SPERMATOPHYTA

Plant woody, evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins derived from (some) sinapyl and particularly coniferyl alcohols, thus containing p-hydroxyphenyl and guaiacyl lignin units, (lignins derived from p-coumaryl alcohol, i.e. S [syringyl] lignin units); true roots present, apex multicellular, xylem exarch, and branching endogenous; arbuscular mycorrhizae +; shoot apical meristem multicellular, interface specific plasmodesmatal network; stem with ectophloic eustele, endodermis 0, xylem endarch, branching exogenous; vascular tissue in t.s. discontinuous by interfascicular regions; vascular cambium + [xylem ("wood") differentiating internally, phloem externally]; wood homoxylous, tracheids and rays alone, tracheid/tracheid pits circular, bordered; mature sieve tube/cell lacking functioning nucleus, plastids with starch grains; phloem fibres +; stem cork cambium superficial, root cork cambium deep seated; leaves with single trace from sympodium ["nodes 1:1"]; stomata ?; leaf vascular bundles collateral; leaves megaphyllous [determinancy evolved first, then ad/abaxial symmetry], spiral, simple, lamina with vein density up to 5 mm/mm² [mean for all non-angiosperms 1.8]; axillary buds associated with at most some leaves; prophylls [including bracteoles] two, lateral; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores, i.e. no distal pore for release of gametes] +, grains mono[ana]sulcate, exine and intine homogeneous; ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, to ca 2 mm from receptive surface to egg, gametes two, developing after pollination, with cell walls, with many flagellae; female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large", first cell wall of zygote transverse, embryo straight, endoscopic [suspensor +], short-minute, with morphological dormancy, white, cotyledons 2; plastid transmission maternal; two copies of LEAFY gene, PHY gene duplications [three - [BP [A/N + C/O]] - copies], nrDNA with 5.8S and 5S rDNA in separate clusters; mitochondrial nad1 intron 2 and coxIIi3 intron and trans-spliced introns present.

MAGNOLIOPHYTA

Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], S [syringyl] lignin units common, positive Maüle reaction [syringyl:guaiacyl ratio more than 2-2.5:1], and hemicelluloses as xyloglucans; root apical meristem intermediate-open; root vascular tissue oligarch [di- to pentarch], lateral roots arise opposite or immediately to the side of [when diarch] xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0; shoot apex with tunica-corpus construction, tunica 2-layered; reaction wood ?, with gelatinous fibres; starch grains simple; primary cell wall mostly with pectic polysaccharides, poor in mannans; tracheid:tracheid [end wall] plates with scalariform pitting, wood parenchyma +; sieve tubes enucleate, sieve plate with pores (0.1-)0.5-10< µm across, cytoplasm with P-proteins, cytoplasm not occluding pores of sieve plate, companion cells from same mother cell that gave rise to the sieve tube; sugar transport in phloem passive; nodes unilacunar [1:?]; stomata with ends of guard cells level with pore, paracytic, outer stomatal ledges producing vestibule; leaves petiolate, lamina [formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, veins (1.7-)4.1(-5.7) mm/mm², endings free; most/all leaves with axillary buds; flowers perfect, pedicellate, polysymmetric, parts spiral [esp. the A], free, numbers unstable, development in general centripetal; P not sharply differentiated, with a single trace, outer members not enclosing the rest of the bud, often smaller than inner members; A many, filament not sharply distinguished from anther, stout, broad, with a single trace, anther introrse, tetrasporangiate, sporangia in two groups of two [dithecal], ± embedded in the filament, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally by action of hypodermal endothecium, endothecial cells elongated at right angles to long axis of anther; tapetum glandular, binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, tectum continuous or microperforate, ektexine columellar, endexine thin, compact, lamellate only in the apertural regions; nectary 0; G free, several, ascidiate, with postgenital occlusion by secretion, stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, dry [not secretory]; ovules few [?1]/carpel, marginal, anatropous, bitegmic, micropyle endostomal, outer integument 2-3 cells across, often largely subdermal in origin, inner integument 2-3 cells across, often dermal in origin, parietal tissue 1-3 cells across [crassinucellate], nucellar cap?; megasporocyte single, hypodermal, megaspore tetrad linear, functional megaspore chalazal, lacking sporopollenin and cuticle; female gametophyte four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; P deciduous in fruit; seed exotestal; pollen binucleate at dispersal, trinucleate eventually, germinating in less than 3 hours, pollination siphonogamous, tube elongated, growing at 80-600 µm/hour, with pectic outer wall, callose inner wall and callose plugs, growing between cells, penetration of ovules via micropyle [porogamous] within ca 18 hours, distance to first ovule 1.1.-2.1 mm, tube moves between nucellar cells; double fertilisation +, endosperm diploid, cellular [micropylar and chalazal domains develop diffently, first division oblique, micropylar end initially with a single large cell, divisions uniseriate, chalazal cell smaller, divisions in several planes], copious, oily and/or proteinaceous, embryo cellular ab initio, minute; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)_n]; whole genome duplication, ndhB gene 21 codons enlarged at the 5' end, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and three copies of the PHY gene, [PHYB [PHYA + PHYC]].

Evolution. Possible apomorphies for flowering plants are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear. This is because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable homoplasy as well as variation within and between families of the ANITA grade in particular for several of these characters, and also because details of relationships among gymnosperms will affect the level at which some of these characters are pegged. For example, if reticulate-perforate pollen is optimized to the next node on the tree (see Friis et al. 2009 for a discussion), it effectively makes the pollen morphology of the common ancestor of all angiosperms ambiguous... For other features such as details of sugar transport in the phloem, their placement on the tree is frankly speculative. Finally, for features such as parietal tissue/a nucellus only one (Nymphaeales) to three cells thick above the embryo sac and a stylar canal lacking an epidermal layer, although plesiomorphous for basal grade angiosperms (Williams 2009), I am unsure where on the tree a thicker nucellus and a stylar epidermal layer are acquired.

[NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]]: vessels +, elements with elongated scalariform perforation plates; wood fibres +; axial parenchyma diffuse or diffuse-in-aggregates; tectum reticulate-perforate [here?]; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.

ASPARAGALES + COMMELINIDS: style long.

Evolution. Divergence & Distribution. The age of this clade has been estimated at 118-116 million years before present (Bremer 2000b; Leebens-Mack et al. 2005).

Style length is variable, and it is unclear exactly where it should be placed on the tree.

ASPARAGALES Link  Main Tree, Synapomorphies.

Chelidonic acid +, steroidal saponins 0 [exact position where?]; (velamen +); (dimorphic root hypodermal cells +); anthers longer than wide; tapetal cells bi- to tetranuclear; microsporogenesis simultaneous; seeds exotestal, tegmen not persistent; endosperm helobial; mitochondrial sdh3 gene lost. - 14 families, 1122 genera, 26070 species.

Evolution. Divergence & Distribution. Stem group Asparagales are dated to ca 122 million years before present, crown group Asparagales to ca 119 million years before present (Janssen & Bremer 2004), although Wikström et al. (2001) had suggested dates of 107-98 and 101-94 million years before present respectively. The topology within Asparagales, especially near the base, in the latter study differs substantially from that used here, while Janssen and Bremer (2004), although not putting Orchidales sister to the rest of the order, placed it (in terms of time) near the beginning of divergence within it, and the topology of their tree also differs considerably in detail from that below. Comparable figures in Magallón and Castillo (2009) are ca 133.1 (stem) and 125 (crown) and 118.6 (stem) and 112.6 (crown) million years for relaxed and constrained penalized likelihood datings respectively.

Magallón and Castillo (2009) suggest that Asparagales have the highest diversification rate in the monocots, about the same as Poales, but in both the rate is little over half that of Lamiales, the clade with the highest rate; Magallón and Sanderson (2001) did not give estimates for the group. Within the clade, the diversity of Orchidaceae is indeed remarkable, but remember it has to be compared with that of all other Asparagales, somewhat less species-rich, perhaps, but a morphologically rather motley crew (see also below, under Orchidaceae).

Chemistry, Morphology, etc. Asparagales commonly have Arum-type arbuscular mycorrhizae, while in Liliales these mycorrhizae are commonly Paris-type (see F. A. Smith & Smith 1997). Storage mannans in the vegetative tissues are scattered in this clade, being known from Xanthorrhoeaceae-Asphodeloideae, Amaryllidaceae and Orchidaceae, but they are uncommon in other orders (Meier & Reid 1982); mucilage polysaccharides in the roots of Asparagaceae-Asparagoideae may also have a storage role.

Three-trace tepals are found in Orchidaceae, Amaryllidaceae-Amaryllidoideae, Iridaceae, Asphodelaceae (but not Kniphofia, Ashpodelus), Asparagaceae-Agavoideae, Amaryllidaceae-Agapanthoideae, and Hemerocallidaceae; one-trace tepals in Ruscaceae (but not Maianthemum stellatum), Amaryllidaceae-Allioideae, Aphyllanthoideae, and Asparagoideae. Scilloideae have tepals with both kinds of vasculature, Urginea even having five traces in the outer whorls (see especially Chatin 1920). Where changes in microsporogenesis are to be placed on the tree is not clear. Furthermore, Rudall (2001a, see also 2002, 2003a) included an inferior ovary as a synapomorphy of the order, noting that in "higher" Asparagales there may well be a reversal to superior ovaries that is associated with the presence of infralocular septal nectaries (as in Xanthorrhoea and Johnsonia (Xanthorrhoeaceae-Xanthorrhoeoideae and -Hemerocallidoideae). However, since superior ovaries are also scattered through the "lower" Asparagales, where the evolution of different ovary morphologies are to be placed in the tree is unclear; ovary position seems a much more flexible character here (and elsewhere) than it has generally been given credit for.

For flavonoids, see Williams et al. 1988), for ovule and seed, see Shamrov (1999a) and Oganezova (2000a, b), for cytology, see Tamura (1995), for root morphology, see Kauff et al. (2000), for general morphology, see Rudall (2003a), for pollen of Japanese representatives, see Handa et al. (2001), for cytology and genome size, see Pires et al. (2006), and for the distribution of taxa with phytomelan and/or with baccate fruits, see Rasmussen et al. (2006).

Phylogeny. The tree is based largely on the analyses in Chase et al. (2000a) and Fay et al. (2000: successive weighting). These studies differ little in detail, although the analysis of Fay et al. (2000) hardly suprisingly had more nodes in the core Asparagales with strong support. For the Amaryllidaceae + Agapanthaceae node, see Meerow et al. (2000b); relationships between Aphyllanthaceae, Themidaceae and Hyacinthaceae might be better represented as trichotomy (these families are now subsumed in a broadly drawn Alliaceae and Asparagaceae). A phylogeny presented by McPherson and Graham (2001) is largely congruent with this, although its sampling is much poorer. Understanding the relationships of Boryaceae and Orchidaceae is critical. Boryaceae have sometimes been placed as sister to Orchidaceae(e.g. Chase et al. 1995a; McPherson & Graham 2001), although with rather weak support, and there are other topologies, including the embedding of Orchidaceae in a paraphyletic Boryaceae-Hypoxidaceae clade (Li & Zhou: 2007: little support).

Recent work suggests that Orchidaceae are sister to other Asparagales (e.g. 76% bootstrap support in Graham et al. 2006; about the same in Givnish et al. 2006b; stronger [96-99%] in Pires et al. 2006, good sampling and seven genes from two compartments), and this is associated with more or less strong support for Boryaceae being sister to the Blandfordiaceae et al. clade. Rudall (2003a) had also suggested a close morphological relationship between Boryaceae and Blandfordiaceae. Note, however, while there is good support in Chase et al. (2006) for the position of Orchidaceae as sister to all other Asparagales, Boryaceae are placed immediately above the Blandfordiaceae et al. clade, albeit with very little support. Some phylogenetic reconstructions of Hilu et al. (2003: molecular data) had suggested Asparagales might be paraphyletic, with Orchidaceae separate from the rest. Rudall (2003a: morphological data) suggested that there was a close morphological relationship between Hypoxidaceae and Orchidaceae in particular. All in all the position of Orchidaceae as sister to the rest of Asparagales, with Boryaceae being part of the Blandfordiaceae et al. clade, seems the best hypothesis, and this hypothesis of relationships is adopted here. Note that this rather changes the characterisation of Asparagales, some characters previously considered to characterise the clade as a whole now being best moved to the subbasal node in the clade (cf. versions 6 and younger of this site).

Previous Relationships. Dahlgren et al. (1985) - basically about the time our understanding of relationships in monocots began to be seriously re-evaluated - recognised two major groups into which they placed most of the "lily-like" monocots. Although corresponding in part to the Asparagales and Liliales as recognised here, and divided by features including patterning of the tepals, absence of phytomelan (both features of their Liliales), etc., both Iridaceae and Orchidaceae were included along with families here included in Liliales. More recently, genera of Boryaceae have often been included in Anthericaceae, as by Takhtajan (1997).

Includes Amaryllidaceae, Asparagaceae, Asteliaceae, Blandfordiaceae, Boryaceae, Doryanthaceae, Hypoxidaceae, Iridaceae, Ixioliriaceae, Lanariaceae, Orchidaceae, Tecophilaeaceae, Xanthorrhoeaceae, Xeronemaceae.

Synonymy: Asparagineae J. Presl, Asphodelineae Thorne & Reveal, Hyacinthineae Link, Iridineae Engler - Agavales Hutchinson, Alliales Berchtold & J. Presl, Amaryllidales Link, Apostasiales Martius, Asphodelales Doweld, Asteliales Dumortier, Gilliesiales Martius, Hypoxidales Martius, Iridales Rafinesque, Ixiales Lindley, Narcissales Dumortier, Orchidales Rafinesque, Tecophilaeales Reveal, Xanthorrhoeales Reveal & Doweld

ORCHIDACEAE Jussieu, nom. cons.   Back to Asparagales

Mycorrhizal herbs, protocorms mycoheterotrophic, root hairs often lacking [?distribution]; flavone C-glycosides, flavonols +, chelidonic acid?; SiO₂ bodies [stegmata] in leaf vascular bundle sheaths, these sheaths with fibres, (also fibre bundles in leaves); flowers monosymmetric, resupinate; T free, median inner T forms a labellum; A 3 [median of outer whorl and laterals of inner whorl], basally adnate to style; tapetal cells uninucleate; ovary inferior, septal nectaries 0, placentae branched, style solid, stigma wet; ovules ca 1500+/carpel, parietal tissue absent, funicle not vascularized; fruit dehiscing laterally by six valves, (indehiscent, ± baccate); seeds minute, dust-like, phytomelan 0; fruit splitting down its sides, T deciduous in fruit; endosperm barely developing, lost at maturity, embryo minute, undifferentiated, suspensor often haustorial (and branched); x = 7?

880[list]/22,075 - five subfamilies below. World-wide. [Photo - Flower]

1. Apostasioideae Horaninov

Chemistry unknown; vessel elements in roots often with simple perforation plates, (vessels in stem +); stomata tetracytic; leaves spiral, vernation plicate; flowers rather weakly monosymmetric, (not resupinate - Apostasia); T develop from a ring primordium, apiculate, carinate, (labellum 0 - Apostasia); (A 2, staminode +/0 - Apostasia); pollen reticulate, (operculate); micropyle bistomal; (embryo sac bisporic - Allium type - Neuwiedia); seeds entotestal, exotegmen sclerified [Neuwiedia], outer periclinal walls collapsing; n = 24.

2/16. Sri Lanka, N.E. India to N.E. Australia, Japan (map: from Pridgeon et al. 1999).

Synonymy: Apostasiaceae Lindley, Neuwiediaceae Reveal & Hoogland

Vanilloideae [Cypripedioideae [Orchidoideae + Epidendroideae]]: C-glycosyl flavones, (saponins), 6-hydroxy flavonols +; (velamen +; tilosomes +); vessel elements with scalariform perforation plates; leaves spiral or two-ranked; flowers strongly monosymmetric; (tepal nectaries +), abaxial outer tepal develops after inner whorl, labellum strongly differentiated; the style and A almost completely congenitally fused [gynostemium], anthers to 2x as broad as long; pollen sticky; placentation parietal, stigma asymmetrical; ovules not fully developed at pollination; fertilisation may take some months; seeds dispersed before maturity of embryo; radicle 0.

2. Vanilloideae Szlachetko

Plant sympodial or monopodial, (echlorophyllous and/or viny); SiO₂ bodies 0; stomata tetracytic; (venation reticulate); calyculus +; T often carinate, (margins of labellum fused with column - some Vanilleae); A 1 [median member of outer whorl], staminodes 2 [from inner whorl], anther incumbent [bent forward, by massive expansion of the apical column/connective]; "pollinia" soft, viscidium 0, (pollen in tetrads; polyporate); (placentation axile), rostellum [ridge, part of median stigmatic lobe] +; (T persistent in fruit), (fruit baccate); seeds fusiform, crustose, exotestal [outer parietal wall well developed], tegmen persisting; endosperm to 16-nucleate; n = 9, 10, 12, 14-16, 18, etc.

15/180: Vanilla (100), Epistephium (12). Pantropical, esp. Asia; Australia, some N. America (map: from Pridgeon et al. 2003).

Synonymy: Vanillaceae Lindley

Cypripedioideae [Orchidoideae + Epidendroideae]: ?

3. Cypripedioideae Kosteletzky

(Stomata paracytic); leaf vernation conduplicate or plicate; 2 abaxial T of outer whorl connate, labellum saccate; A 2 [from inner whorl], staminode 1 [median member of outer whorl]; tapetal cells binucleate; microsporogenesis successive?; pollen ± psilate (foveolate), operculate, (in tetrads); median stigma lobe largest; (micropyle bistomal); embryo sac bisporic, eight-celled [Allium-type]; (T persistent in fruit); n = 9 or more.

5/130: Paphiopedilum (62), Cypripedium (50). Mostly (warm) temperate N. Hemisphere, East Malesia and tropical South America (S. India) (map: from Hultén 1958; Pridgeon et al. 1999). [Photo - Flower]

Synonymy: Cypripediaceae Lindley

Orchidoideae + Epidendroideae: floral primordium tranversely elliptic-oval; labellum initiated first; A 1 [median member of outer whorl], (staminodes 2 [from inner whorl]); microsporogenesis simultaneous [tetrads tetrahedral]; pollen in pollinia attached to sticky viscidium, pollinium/pollinarium stalk variously formed from part of the anther [caudicula], epidermis of the rostellum [tegula] or apex of the rostellum [hamulus], pollen usu. in tetrads, porate or ulcerate; median carpel developed before the others, rostellum [ridge, part of median stigmatic lobe, viscidium is also part of it] +; T persistent in fruit; tegmen not persisting; endosperm not developing at all; n = 9 or more [19 common].

4. Orchidoideae Eaton

Plant sympodial; mycoheterotrophs rare, stem/root tuber common; (glucomannans +); SiO₂ bodies 0; sclerenchyma in leaf [as fibre bundles or associated with vascular bundles] and stem rare; stomata anomocytic; leaves usu. spiral, soft, herbaceous, deciduous; anther erect (incumbent), apex acute, staminodes reduced; (hamulus [pollinium stalk from modified apical part of rostellum] +), pollinia soft/sectile; n = 12-24 [x = 7?].

208/3755: Habenaria (600), Caladenia (376), Platanthera (200), Pterostylis (200), Disa (175), Cynorkis (125), Orchis (125), Corybas (120), Goodyera (80-100), Satyrium (90), Disperis (85), Prasophyllum (80), Cyclopogon (75), Pelexia (75), Peristylus (75), Zeuxine (70), Diuris (55), Goodyera (55), Holothrix (55), Cheirostylis (50), Dactylorhiza (50), Thelymitra (50). World-wide, esp. temperate (map: from Pridgeon et al. 2001, 2003; distribution in N. Asia and N. North America unclear).

Synonymy: Neottiaceae Horaninow, Limodoraceae Horaninow, Liparidaceae Vines, Ophrydaceae Vines

5. Epidendroideae Kosteletzky

Epiphytes common, plant often then sympodial, (plant without shoots or leaves [Vandeae]; mycoheterotrophic); (SiO₂ bodies 0); velamen + (0), (roots with pneumathodes); stomata often para- or tetracytic; stems thick; leaves usu. distichous, vernation conduplicate (plicate), articulated with sheathing base (not), (unifacial, terete or equitant); anther incumbent [bent forward by column elongation, or by very early anther bending (vandoids)], (strongly convex), with beak, operculate, pollinia clavate, hard, (sectile), [pollinium stalk from apical part of median stigma lobe] +, pollen inaperturate[?]; (inside of carpel wall with hairs); (cotyledon visible); n = 5+.

650/18000: Bulbophyllum (2035), Epidendrum (1500), Dendrobium (1400), Pleurothallis (1000), Lepanthes (>800), Stelis (700), Oncidium (520), Masdevallia (410), Liparis (320), Malaxis (300), Maxillaria (ca 300), Crepidium (280), Dendrochilum (265), Calanthe (260), Acianthera (200), Coelogyne (200), Specklinia (200), Angraecum (200), Eulophia (200), Phreatia (190), Oberonia (175), Taeniophyllum (170), Phreatia (160), Pinalia (160), Telipogon (160), Octomeria (150), Gomesa (125), Cyrtochilum (120), Dracula (120), Encyclia (120), Dichaea (110), Trichosalpinx (110), Ceratostylis (100), Catasetum (100), Elleanthus (100), Glomera (100), Prostheacea (100), Sobralia (100), Camaridium (80), Brassia (75), Platystela (75), Brachionidium (65), Appendicula (60), Callostylis (60), Comparettia (60), Neottia (60), Nervilia (60), Notylia (60), Podochilus (60), Scaphyglottis (60), Sophronitis (60), Ornithidium (55), Fernandezia (50), Lepanthopsis (50), Maxillariella (50), Restrepia (50), Rodriguesia (50). More or less world-wide, but most diverse in the tropics; rather poorly developed in Australia (map: from Pridgeon et al. 2005).

• Orchidaceae can be recognised by their strongly monosymmetric flowers in which the 1-3 stamens are at least basally adnate to the style. The flowers are usually held with the median member of the outer tepalline whorl in the adaxial position, while the median member of the inner whorl is often remarkably elaborated and forms a labellum. The ovary is inferior and the fruit, a capsule, opens down the sides to release the very numerous and minute seeds.

• Apostasioideae have 2-3 stamens that are connate only to the base of the style and apiculate, carinate tepals. The other subfamilies have a well developed labellum and the stamen(s) are more or less completely fused with the style, forming a gynostemium.

• Cypripedioideae have two stamens and a deeply saccate labellum. The other subfamilies have but a single stamen. In the other subfamilies the labellum is very variable in shape, but not often deeply saccate. Vanilloideae lack both pollinia and viscidia, while both are present in Epidendroideae and Orchidoideae. The former have rather tough leaves and stems and incumbent anthers, the latter often have softer, deciduous leaves and straight anthers.

Evolution. Divergence & Distribution. Stem group Orchidaceae are dated to ca 119 million years before present, crown group Orchidaceae to ca 111 million years before present (Janssen & Bremer 2004), although the crown group age estimates of Ramírez et al. (2007: calibration by Miocene Goodyerinae pollinaria found in amber, see especially Supplmentary Table; penalized likelihood and nonparametric rate smoothing) are somewhat younger, (90-)84-76(-72) million years before present; other estimates include (105-)80-77(-56) million years (Gustafsson et al. 2010: BEAST, but see also Wikström et al. 2001, considerably younger; Bouetard et al. 2010, slightly older estimates). Ramírez et al. (2007) suggest that the subfamilies had diverged by the end of the Cretaceous, ca 65 million years before present, or perhaps slightly later in the early Palaeocene, and that orchid radiation was a Tertiary phenomenon; dates suggested by Gustafsson et al. (2010) are somewhat younger, major diversification perhaps occurring during the cooler period at the end of the Eocene and into the Oligocene, rather that during the thermal maximum earlier in the Eocene (cf. Ramírez et al. 2007).

Estimates of the time of crown group diversification in Epidendroideae are (72-)68-51(-44)/(62-)49-44(-29) million years ago, with "higher epidendroids", the speciose, epiphytic Epidendroideae in particular, beginning to diverge in the Eocene some (64-)59-42(-36)/(49-)39-34(-22) million years before present (Ramírez et al. 2007; Gustafsson et al. 2010; see also Conran et al. 2009a). Wikström et al. (2001) had suggested divergence between the single member of Cypripediodeae and Epidendroideae included in their analysis as being much more recent, only ca 37-36 million years before present. Crown group Vanilloideae diverged (76-)71-62(-58)/(79-)58-57(-39) million years ago (Ramirez et al. 2007; Gustafsson et al. 2010). Other crown group ages are (54-)49-44(-39)/(66-)43-41(-23) million years for Apostasioideae, (62-)56-34(-30)/(50-)33-31(-17) million years for Cypripedioideae, and (65-)61-52(-48)/(67-)53-50(-34) million years for Orchidoideae (Ramirez et al. 2007; Gustafsson et al. 2010). Using an age for the clade of 71 million years, Bouetard et al. (2010) estimated that crown group Vanilla started to diversify ca 34 million years ago, at least three instances of long distance dispersal being needed to explain its present distribution.

Normally neither orchids nor pollinating insects are diverse on oceanic islands, but angraecoid orchids are surprisingly diverse on the Mascarene islands, and Reunion in particular also has a diverse insect fauna (Micheneau et al. 2008).

Endress (2011a) thought that the inferior ovary in Asparagales might be a key innovation, although where this feature should be placed on the tree is unclear - perhaps here is one place. The presence of pollinia is another feauture that he mentioned; this is probably best placed as a synapomorphy of the [Orchidoideae + Epidendroideae] clade. But complicating any simple story about the diversification of Orchidaceae based simply on numbers of species in families, they are sister to the rest of Asparagales which are also morphologically very diverse and include some 6,850 species, and Asparagales as a whole are sister to commelinids, with some 22,750 species. Within Orchidaceae, clades of 16, 180, and 130 species are successively sister to the rest of the family, so numbers and sister-group relationships alone tell very little of the story (as do the rate shifts suggested in Smith et al. 2011). Indeed, we know little about the origin and biogeography of the family (see also Chase 2003), although the bulk of the diversification seems to be a Tertiary phenomenon (Gustafsson et al. 2010, etc. - see above), and the shift to the epiphytic habit and the associated adoption of CAM photosynthesis is likely to have been important (see below). Finally, although Orchidaceae are considered to be very diverse, much of the floral variation is at one level only a series of intricate combinations of a rather limited theme - most species have a single anther, a labellum, a very similar gynoecium, etc., although the variations of the pollinaria formed by the single anther and particularly the protean elaborations of the labellum are remarkable.

The presence of well-developed and effective premating barriers (see below) may have obviated any pressure for the selection of postmating barriers, hence the ease with which artificial crosses can be made. Thus artificial hybrids involving three or more genera have been reported, but how these will look when generic boundaries are redrawn is unclear. Nevertheless, many Orchidaceae can be crossed artificially, as, for instance, many genera in Laeliinae (van den Berg et al. 2000, 2009). Interestingly, it has been suggested (based on work on European orchids) that in those orchids with generalized food-deceptive mating mechanisms, barriers to crossing may in fact be postzygotic, whereas those that practice sexual deception have premating reproductive barriers (Cozzolino & Scopece 2008).

Some of the distinctive features of the family seem to be biologically connected. Thus pollinia ensure the fertilization of numerous ovules; the minute seeds that result are usually devoid of endosperm or differentiated embryo, and the obligate myco-heterotrophy of the young plant may compensate for the absence of seed reserves (Johnson & Edwards 2000 in part; Eriksson & Kainulainen 2011). Gravendeel et al. (2004 and references; see also Peakall 2007) list the numerous hypotheses that have been advanced to explain the diversity of Orchidaceae; these include pollinator specialization, niche partitioning, habitat fragmentation, wide dispersal of the seeds, etc.

Plant-Animal Interactions. Members of Orchidaceae are not often eaten by butterfly caterpillars (Janz & Nylin 1998) or by insect herbivores in general, although Riodininae-Riodininae larvae may be found on them (Hall 2003 and references).

Floral Biology & Seed Dispersal. Tremblay et al. (2005) reviewed the evolutionary consequences of variation in sexual reproduction in orchids, and Orchidaceae are of course noted for the diversity of their pollination mechanisms and the remarkable variation shown by their flowers. Orchid diversification is often explained in terms of the close association between pollinators and individual species of orchids, but recent work suggests very strongly that co-evolution should not automatically be assumed (Ramírez et al. 2011, see below), and factors other than floral variation may have contributed to the diversification of Orchidaceae (see Vegetative Variation and Ecology & Physiology below). For summaries of pollination in Orchidaceae, see van der Cingel (1995, 2001), Endress (1994b), etc. - and of course the classic study by Darwin (1862) is still worth reading (see also Yam et al. 2009). For a general discussion on floral evolution in the family, with an emphasis on terata and homeosis s.l., see Rudall and Bateman (2002).

Orchid flowers may be notably long-lived (months!), although some last only for a single day. Flowers are commonly resupinate, the ovary being twisted about 180°, the labellum ending up in the abaxial position (Ernst & Arditti 1994; Yam et al. 2009 for reviews). However, the amount of resupination often varies within a plant, especially when the inflorescence is arching; here all flowers of the inflorescence are often oriented so that their labellum is in the same position with respect to gravity, with the ovary sometimes being twisted 360° (as in Angraecum, etc.) or not at all. Fischer et al. (2007) discuss the variety of ways - of which twisting of the pedicel is but one of the mechanisms involved - that flowers in the speciose Bulbophyllum present themselves in the Malagasy region. In orchids such as Calopogon the flowers are never resupinate, and all flowers on the erect inflorescence show "normal" monocot orientation, the labellum here being adaxial. In the dioecious Catasetum resupination varies between staminate (presented resupinate) and carpellate (not resupinate) flowers (see below).

The most conspicuous element of floral variation is the labellum, a highly-differentiated member of the inner whorl of tepals, which shows a truly remarkable diversity of form and colour (Rudall & Bateman 2002); duplication of genes may be involved in this (Mondragón-Palomino & Theißen 2008). The spatial relationships of the labellum and column in particular force the pollinator to approach the flower in a particular way, and in general, the pollinaria are very precisely placed on the pollinator, closely related orchid species differing in exactly where on the animal their pollinaria are placed (e.g. Maad & Nilsson 2004). There is quite often movement of the pollinia after attachment of the pollinarium to the pollinator to bring them into the proper position for pollination (for pollinia, see Selbyana 29: 1-86. 2008, and references).

In general, reproduction may often be pollinator-limited (Tremblay et al. 2005), with few flowers on an inflorescence producing seeds, however, the production of huge numbers of seeds by each fruit may compensate for this - orchids "specialize in chance" (Pérez-Hérnandez et al. 2011). The plesiomorphic condition for the family may be to lack nectar (Jersáková et al. 2006), pollen alone being collected from flowers of Apostasioideae; all told, some 8,000 species of orchids lack nectar altogether. However, nectaries do occur, and they vary in position (Davies et al. 2005) although they are never septal; nectar is in fact a common reward (Bernadello et al. 2007 and references). In a number of species of Maxillaria hairs on the labellum contain protein and perhaps also starch and function as pseudopollen, so rewarding the pollinator (Davies et al. 2000; Davies 2009), while in some orchids, oil is a reward (e.g. Chase et al. 2009; Steiner 2010, and references). Perhaps 60% of orchids are pollinated by bees (Schoonhoven et al. 2005), deceived or otherwise (see below for more details).

Cozzolini and Widmer (2005; see also Schiestl 2005) suggested that orchid diversification is associated with the deceptive pollination mechanisms that are so prevalent in the family; about one third of the species - estimates range from 6,500 to 10,000 - are pollinated in this way (Schiestl 2005, 2010 for reviews, the latter brief; Schlüter & Schiestl 2008 for molecular mechanisms; Peakall 2009 for deceit and speciation; Schaefer & Ruxton 2010 and references for exploitation of perceptual biases of the pollinator by the plant; Gaskett 2011 for the pollinator's point of view in sexual deception). Interestingly, recent studies suggest that when pollinators visit orchid flowers in the course of deceptive pollination or to pick up scent rewards, pollinator specifity is greater and species richness is greater than when pollinators visit for nectar (Schiestl & Schlüter 2009; see also Scopece et al. 2010a for pollination efficiency). Thus deceit pollination may under certain situations increase outcrossing and speciation, the latter perhaps because of the specificity of the pheromones produced by the plants (Jersáková et al. 2006; see also Ledford 2007).

The European Ophrys (Orchidoideae) is well known for its distinctive and variable labellum and production of chemicals that are very similar to insect pheromones; together, these enable the flower to mimick female insects (Cortis et al. 2009 and references): Pollination occurs as bees and wasps in particular attempt to copulate with the flowers (Kullenberg 1961). Alkenes (hydrocarbons with at least one double bond) are involved in the chemical component in this mimicry (e.g. Stökl et al. 2009; Ayasse et al. 2011), and such chemicals are common in related genera as well (Schiestl & Cozzolino 2008). However, there is currently discussion as to the limits of species in this clade; certainly, hybridization between some of the sspecies is well known. The result is that current estimates of species numbers in Ophrys range from 16 to 215, although the former number seems closer to "reality" (Vereecken et al. 2011; Bateman et al. 2006a, 2011a; Devey et al. 2008). In the Australian Chiloglottis there is a fair degree of congruence between the phylogenies of orchid and deceived wasps (Mant et al. 2002), but again, understanding species limits is critical; here there seem to be a number of crypric species (Griffiths et al. 2011). Flowers of Serapias (Bellusci et al. 2008 for a phylogeny) may even attract pollinators by mimicking a nest hole.

Fly pollination is common in Orchidaceae (Christensen 1994), most taxa being members of Epidendroideae. Fly pollination is common in the highly speciose and largely Old World Bulbophyllum. There dark-coloured flowers with carrion scent, a mobile labellum, and often dangling hairs of various kinds are common, but a number of taxa have sweet, fruity scents aand lighter-coloured flowers and are pollinated by fruit flies - which may also be commercially important pests (Tan 2008 and references, see also Texeira et al. 2004; Fischer et al. 2007 for resupination). In the New World, pollination during pseudocopulation with fungus gnats (dipterans, often Sciaridae) has been reported in the large genus Lepanthes (Blanco & Barboza 2005). However, details of how this system functions is unclear since there is no obvious connection between the morphology of the orchid flower and that of the fungus gnat (Singer 2011). Be that as it may, fly pollination of one sort or another (with nectar reward, or sapro- or mycomyophily) is likely to predominate in the some 4,000+ species of Pleurothallidinae, to which Lepanthes belongs (Borba et al. 2011).

Orchids that secrete oil in their flowers may show convergence with the flowers of other oil-pollinated plants. Thus pollination of some South African Orchidoideae-Coryciinae (e.g. Disperis) is by oil-collecting bees; the flowers have paired, pouch- or spur-like structures like those of another local oil plant, Diascia (Scrophulariaceae: Pauw 2006). Moreover, the distinctive lip-like appendage that was a defining feature of the old Corycinae (Waterman et al. 2009) seems to have evolved in parallel, although relationships are not entirely clear. Steiner (2010) discussed pollination of the oil flowers of the South African Huttonaea, perhaps immediately unrelated, while Steiner et al. (2011) analyzed scent composition of many southern African oil-secreting Diseae. The African Satyrium also has flowers with two spurs, although there nectar is the floral reward (Johnson et al. 2011a). Oncidiinae may have elaiophores, sometimes on the labellum, and with their radiating, clawed, yellow or purple "petals" may mimic Malpighiaceae, both groups being visited by bees like Centris, etc., and providing distinctive oils as a reward (Reis et al. 2007; Neubig et al. 2012). However, species with malpig-like flowers may lack rewards, and these species are then Batesian mimics of Malpighiaceae; M. P. Powell (in Neubig et al. 2012; some species may mimic Calceolaria, another oil flower) has estimated that such mimicry may have evolved at least 14 times within Ocidiinae. Since the old Oncidium was based on floral characters, it is hardly surprising that it is hopelessly polyphyletic (Stpiczynaska & Davies 2008; Chase et al. 2009; Neubig et al. 2012). For a summary of what little is known of oil flowers in Orchidaceae, which have evolved probably at least a dozen times, eight times in Maxillarieae alone, see Renner and Schaefer (2010). Examples of butterfly, moth and even bird pollination are also well known. As an example of moth pollinated orchids, the corolla tube of Angraecum sesquipedale, from Madagascar, is ca 30 cm long, and its pollinator for long remained unknown, although Darwin (1862) suggested that some moth with a proboscis that long would be found. Indeed, Xanthopus morgani praedicta, with a proboscis length of ca 25 cm, was subsequently discovered (Nilsson et al. 1987; Nilsson 1988: Micheneau et al. 2010 discuss pollination in angraecoid orchids). For spurs, nectariferous and otherwise, in Orchidoideae-Orchidinae, see Bell et al. (2009), and for the great floral and pollinator diversification in some of its genera, including Disa, see Johnson et al. (1998) and Bytebier et al. (2007), in Satyrium, see Johnson et al. (2011a), and in the largely Australian Diurideae, see the summary in Weston et al. (2011: various kinds of mimicry, nectar evolved [and lost] many times, etc.).

Williams (1982) discussed the general importance of male euglossine bees in orchid (Epidendroideae) pollination in the neotropics; male bees searching for fragrances are usually involved, and the some 190 species of bees pollinate perhaps up to 25% of tropical American Orchidaceae, hence their common name, orchid bees. Pollination occurs especially in orchids growing at lower altitudes, and anywhere from >700-2,000 species may be so pollinated (Cameron 2004 and references; Zimmermann et al. 2009 - Photo: see bee pollinators), not to mention hundreds of species of Zingiberales, Gesneriaceae, Lecythidaceae, etc. The pollination of Catasetinae by male euglossine bees which visit the flowers for fragrance compounds is well known (Darwin 1862; Chase & Hills 1992 for a phylogeny; Nicholson et al. 2008 for explosive discharge of pollinaria). Although the bees are effective pollinators, the relationships between orchids and euglossine bees are non-specific on both sides (Cameron 2004). Importantly, divergence of crown-group euglossines occurred 42-27 million years ago (Ramírez et al. 2010), and this is distinctly earlier than the orchids they pollinate (Ramírez et al. 2011). Furthermore, these orchids belong to at least three immediately unrelated clades, so simple insect-orchid co-evolution is unikely to be an explanation for the diversification of euglossine-pollinated orchids - and probably of orchids in general. Indeed, of the compounds that the bees pick up from the orchids they visit, relatively few are found only in these orchids, and they acquire many other fragrances from other sources (Ramírez et al. 2011). Orchids may be exquisitely adapted to individual pollinators whose sensory biases they may exploit (Schiestl 2010), but certainly not all pollinators are tied to a single species of orchid, and in orchid bees the reverse relationships is more frequent (Ramírez et al. 2011). Closely related and sympatric species of Euglossa did show greater disparity in the fragrances they had collected and stored in their hind tibial pockets than might be expected, the distinctive fragrance signals of male orchid flowers perhaps being involved in pre-mating isolation in the bees; overall, however, the most dominant compounds in these fragrances were highly homoplasious (Zimmermann et al. 2009) and it is unlikel;y that any orchid fragrances are unique.

The dioecious Catasetum is pollinated by these bees. Catasetum has rematkable flowers, even for an orchid: Not only does resupination differ between staminate (presented resupinate) and carpellate (not resupinate) flowers, but there are many other striking differences, especially in labellum morphology, between the two - indeed, staminate and carpellate specimens were once put in separate genera, Myanthus and Monachanthus respectively. The attachment of the pollinaria on the bees is by an explosive mechanism (Nicholson et al. 2008), and Romero and Nelson (1986) suggested that the bees were so unpleasantly affected by this process that they subsequently avoided male flowers - hence the very different morphologies of the female flowers...

A final distinctive feature of many orchid flowers is that the ovules are usually not fully developed at anthesis. There are many reports that fertilisation may be delayed relative to pollination, as in Cypripedium and a number of other genera; the time between pollination and fertilization ranges from four days to ten months (in Vanda), the normal time being one week to six months (Wirth & Withner 1959, also Sogo & Tobe 2005, 2006d for references: Fagales show the same correlation. ?Situation in Apostasioideae). Even after fertilization, it may be a month before embryo development begins, as in Sarcanthinae (Wirth & Withner 1959 for references).

Most orchids produce huge numbers of minute dust seeds - up to 4,000,000 seeds per fruit, 74,000,000 seeds per plant, the seeds being as little as 150 µm long or less (Arditti & Ghani 2000; Yam et al. 2009). These are usually devoid of endosperm or a differentiated embryo; although Arditti (1967) suggested that a few species had recognizable cotyledons, the species mentioned are not basal in the tree. Much of the seed, small as it is, is in fact empty space, and the seeds are well suited for wind dispersal (Arditti & Ghani 2000); the obligate myco-heterotrophy of the young plant probably compensates for the absence of seed reserves (Johnson & Edwards 2000 in part; Eriksson & Kainulainen 2011). The subterrananean mycoheterotroph Rhizanthella has baccate fruits with large, crustose seeds (Weston et al. 2011).

Bacterial/Fungal Associations. Orchids characteristically have a very close association between basidiomycete - and some ascomycete - fungi. Rhizoctonia (= Ceratobasidium) is a common anamorph or form genus, and Russulaceae, Tuber, and Sebacinales B (found with autotrophic orchids) and B (with mixotrophic and myco-heterotrophic orchids) are all involved; the most common families are Tulasnellaceae, Ceratobasidiaceae and Sebacinaceae (see Currah et al. 1997 and Yukawa et al. 2009 for a list of the fungi; Otero et al. 2002; Roy & Selosse 2009; Weiß et al. 2009), but some neotropical Epidendroideae have Atractiellomycetes (in the same clade as Puccinia) as mycobionts (Kottke et al. 2010). This association starts as soon as the orchid seed begins to germinate. At this stage sugars and nitrogen move from the fungus to the orchid (Zimmer et al. 2007), and the initial fungus-plant association results in a protocorm (Peterson et al. 1998). However, some orchids can be made to germinate in the absence of a fungus. The fungi form an intracellular mycorrhizal association and are basically modified ectomycorrhizae (Smith & Read 1997), and at least in some cases may also be ectomycorrhizal on forest trees (Bidartondo & Read 2008, see also below). It is perhaps a reflection of this association that Orchidaceae have particularly small seeds when compared with their immediate relatives (Moles et al. 2005a). The specificity of the mycorrhizal association may be connected with the diversification of the family (Otero & Flanagan 2006), although the relationship is by no means one-on-one (see Roche et al. 2010 for the specificity of the basidiomycete Tulasnella-Chiloglottis association; Otero et al. 2011). It is likely that at least some fungi involved in orchid symbioses are in fact saprophytes living on decaying plant material that can also form close relationships with orchids (Ogura-Tsujita et al. 2009; Yukawa et al. 2009).

Details of the fungus-orchid association were until recently unclear in Apostasioideae, although it was known that the fungus Tulasnella was involved, and this genus is also found in Cypripedium, etc. (Kristiansen et al. 2004; see also Roche et al. 2010); Yukawa et al. (2009) have recently studied the associates of Apostasia in some detail. Stomatiferous root tubercules form there as a result of the association with the fungus, and these may make the plant better able to deal with wet conditions (Stern & Warcup 1994); seeds of Apostasioideae are rather larger than those of other orchids. Interestingly, the Australian Boryaceae also have a plant-fungus association - details?

Ecology & Physiology. The obligate association of orchids and fungi is central to understanding the physiology of the young orchid plant, at least. Indeed, myco-heterotrophy, holomycotrophy, is not uncommon in the family, and more or less echlorophyllous myco-heterotrophs may have evolved some 30 or more times in the family (Molvray et al. 2000; Freudenstein & Barrett 2010); a variety of different fungi are involved. Holomycotrophs are most common in ground-dwelling Epidendroideae - about 1 in 10 of the species have this life style (Freudenstein & Barrett 2010). The Australian Rhizanthella (Orchidoideae-Diuridae) is a subterranean holomycotroph, the flowers even opening underground. It has the smallest organelle genome of any land plant, the chloroplast genome being about 59,000 BP, but it maintains a core of functioning genes (Delannoy et al. 2011). In Corallorhiza (Epidendroideae) the fungi involved are several species of Russula which form both an ectomycorrhizal association with adjacent trees and an endomycorrhizal association with the orchid (Taylor & Bruns 1999); individual North American clades in the C. striata complex associated with different sets of fungi (Barrett et al. 2010 - in this case the fungus was Tomentella [Thelephoraceae]). However, bi- or unidirectional (from fungus to orchid) movement of carbon has been detected even in chlorophyllous orchids (Cameron et al. 2008; Tsujita et al. 2009; Hynson et al. 2009a), although of course in holomycotrophic orchids carbon flow is unidirectional.

Epiphytes are common in Orchidaceae, yet mycorrhizal associations are thought to be less common in epiphytic plants (e.g. Janos 1993, but cf. Setaro et al. 2006, 2008 for Ericaceae). In orchids, the epiphytic habitat is particularly favoured by Epidendroideae; all told, about 70% of all Orchidaceae are epiphytes, and there are more species of epiphytic orchids than of all other vascular epiphytes combined (Benzing 1983). Indeed, speciation in Orchidaceae may increase in epiphytic clades, e.g. in Epidendroideae-Bulbophyllinae (Gravendeel et al. 2004). In the epiphytic habitat orchids have to deal with periodic drought and lack of nutrients (Gravendeel et al. 2004, see also Motomura et al. 2008). Twig epiphytes in particular grow on twigs less than 2.5 cm in diameter in very exposed and high light conditions, and some of these minute twig epiphytes, which are concentrated in a clade of the New World Epidendroideae-Cymbidieae-Oncidiinae, mature within a year (Chase 1987; Chase and Palmer 1997; Neubig et al. 2012). The leaves of these small plants are isobifacial and are arranged like a small fan (the psygmoid habit) and they have no pseudobulbs - in both these features they look like very young plants of other Oncidiinae and are more or less paedomorphic (Chase 1987; Neubig et al. 2012 for references; Chase et al. 2005 for genome size); their seeds also have little grapnels, perhaps aiding in attaching to the small twigs on which they grow (Chase & Pippen 1988).

Nyffeler and Eggli (2010b) estimate that some 50+ genera and 2,200 species of orchids - or perhaps double that number - are succulents, whether of stem or leaf, and succulence is appropriate for a habitat in which water availability is uncertain (see also Figueroa et al. 2008); terrestrial orchids have thinner leaves. Finally, a number of epiphytic taxa in Epidendroideae-Vandeae have deciduous or no leaves, the vegetative body consisting of swollen or flattened photosynthetic roots (see below).

The epiphytic habitat is thus similar to dry terrestrial habitats, so it is not surprising that many epiphytic Epidendroideae, perhaps some 7,000 species, are likely to have crassulacean acid metabolism (CAM) photosynthesis (Winter & Smith 1996b); variants of CAM photosynthesis such as CAM-cycling are common among epiphytes (see Cameron et al. 2008 for Oncidiinae). (The numbers of taxa involved are unclear; in a survey of 1,002 Costa Rican orchids, Silvera et al. (2010a) found that only some 10% of Vanilloideae and Epidendroideae showed signs of strong CAM (perhaps 30% more had weak CAM); CAM was not found in Orchidoideae and Cypripedioideae.) The adoption of CAM by epiphytic Epidendroideae growing at low altitudes has been associated with the Tertiary radiation of that subfamily (Silvera et al. 2009); CAM has evolved perhaps ten times in Orchidaceae, and has also reversed to C₃ photosynthesis. Diversity of epiphytic Epidendroideae also occurs at altitudes where humidity and other environmental factors are suitable (Silvera et al. 2009). Of course, Epidendroideae like Malaxis and Liparis are largely terrestrial, probably secondarily so.

Vegetative Variation. It is often forgotten that Orchidaceae show considerable diversity in habit and other vegetative features despite their generally modest size; Tatarenko (2007) outlines the extensive vegetative variation of temperate orchids, i.e. especially Orchidoideae. The leaves are variously folded in bud; they may be quite thin to thick; bifacial, equitant or terete, have massively swollen bases or not; spirally arranged to distichous; while some ground- and shade-dwelling species have distinctive coloured and patterned leaves that makes them particularly attractive to horticulturists. Extrafloral nectaries are scattered in the family, being found on the stems opposite the leaves in Vanilla, at the bases of the pedicels in Cymbidium, etc.

Nyffeler and Eggli (2010b) estimate that some 50+ genera and 2,200 species of orchids (or double that number) are succulents, whether of stem or leaf or even roots; succulence is conspicuous in epiphytic orchids (see also Figueroa et al. 2008). Thus individual leaves of Bulbophyllum may be some and weigh. Many epiphytic taxa in Epidendroideae-Vandeae either lack photosynthetic leaves or have very deciduous leaves, however, the vegetative plant consists largely of photosynthetic roots (rarely the stem is photosynthetic), and such plants have evolved several times. These photosynthetic roots may be stout (ca 5 mm across) and terete, as in , while the aptly named Taeniophyllum has distinctive, flattened, photosynthetic roots (e.g. Carlsward et al. 2006b); all told, over 200 species, all epiphytes, are involved.

These plants, and those of many other Epidendroideae, appear to lack root hairs, although they are apparently developed on the side of the root facing the substrate (von Guttenberg 1968; root hairs ["rhizoids"] are sometimes described as being branched [Rasmussen 1999]). The roots themselves are commonly rather fat; a velamen, which has spiral thickenings on the cell walls, is well developed (von Guttenberg 1968). In addition to the pneumathodes common in Epidendroideae, leafless Vandeae have aeration units in their roots. Theae are made up of distinctive exodermal cells, a space beneath, and a pair of thin-walled cortical cells; such aeration units are also found in related leafy Vandeae (Benzing et al. 1983; Carlsward et al. 2006a, b). How carbon dioxide and water flux are controlled in epiphytes is unclear, especially because there are no stomata in the roots, although the aeration units may be stomata analogues (Benzing et al. 1983; Cockburn et al. 1985). Roots of New World epiphytic Epidendroideae in particular have distinctive tilosomes, cells of the innermost layer of the velamen that are adjacent to the passage cells of the exodermis and that have complex often lignified excrescences developing from the wall (Pridgeon et al. 1983), but such cells are also found in ground-dwelling Orchidoideae-Spiranthinae (Figueroa et al. 2008) and their exact function is unclear.

The End. Returning to the question, Why so many orchids?, it is clear that Orchidaceae are distinctive in several ways, of which their flowers and fruits are just two, and no one feature is likely to be responsible for their diversification. Indeed, Waterman et al. (2011) distinguish between speciation and coexistence in orchids, and note that shifts in details of pollination (placement of pollinaria, pollinating insect) occur with speciation, although associations with different fungi may promote the co-occurrence of immediately unrelated orchid species. But treating Orchidaceae as a whole as the diverse clade in need of explanation is unlikely to be the way to go.

Chemistry, morphology, etc. Orchidaceae seem to be the only clade outside the commelinids with SiO₂ bodies (e.g. , but I am not sure if these bodies are an apomorphy for the family; they are certainly sometimes lost. For the anatomy of Apostasioideae, see Stern et al. (1993); the subfamily is poorly known.

Zygomorphy of the flower in many, but not all orchids - and in Hypoxidaceae and Doryanthaceae - is evident even in the earliest primordia (Kurzweil & Kocyan 2002 and references). A few Orchidaceae have more or less polysymmetric flowers, and in Telipogon (Epidendroideae - Oncidiineae) a polysymmetric perianth becomes evident only late in development (Pabón-Mora & González 2008). The sequence of organ initiation varies considerably within the family (Pabón-Mora & González 2008). Apostasioideae and Cypripedioideae have simultaneous initiation of members of the inner tepal whorl, the plesiomorphic condition for Asparagales (Kocyan & Endress 2001a); have Vanilloideae been studied? At least some Orchidaceae have placentoids (Weberling 1989). Anthers of some species appear to be bisporangiate in early development (Freudenstein & Rasmussen 1996). Prutch and Schill (2000) discuss variation in the morphology and ultrastructure of the stigma; variation seems to be at about the subfamilial level. Although the seeds are generally minute and the testa cells have thin walls, Selenipedium (Cypripedioideae) has a hard, dark testa, although apparently it lacks phytomelan. There is much variation in chromosome number and size. Thus Apostasioideae and Orchidoideae have small chromosomes, while larger chromosomes occur in Cypripedioideae and Vanillioideae; Felix and Guerra (2010) survey chromosome number variation in Epidendroideae. matK in Apostasioideae may be in transition from a possibly functional gene to a pseudogene; in the other members of the family examined (but the sampling is poor) it is a pseudogene (Kocyan et al. 2004).

Additional information is taken from Hirmer (1920: floral morphology), Swamy (1948a: floral vasculature, 1949: endosperm development, embryology), Wirth and Withner (1959: embryology and development), van der Pijl and Dodson (1966: pollination), Rasmussen (1982: pollinarium morphology), Newton and Williams (1978: Cypripedioideae, Apostasioideae pollen), Schill and Pfeiffer (1977: pollen, general), Clements (1995, not read, embryology, etc.), Johnson and Edwards (2000: pollinia morphology), Pacini and Hesse (2002: pollen units), Freudenstein and Rasmussen (1996, 1997) and Freudenstein et al. (2002), all pollinium development, number and type, Pridgeon et al. (1983: tilosomes), Porembski and Barthlott (1988: velamen), Schlechter (1992, 1996, 2003: general), Stern et al. (1993b: vegetative anatomy), Dressler (1993: general), Endress (1994b: floral morphology), Freudenstein and Rasmussen (1999: morphological phylogeny), Rasmussen (1999: terrestrial orchids), Kurzweil (2000), Molvray et al. (2000), Cameron and Chase (2000), Szlachetko and Rutkowski (2000) and Szlachetko and Margonska (2002), both gynostemium, Kocyan and Endress (2001a: floral development), Kristiansen et al. (2001), Johansen and Frederiksen (2002: flowers), Cameron (2002), Kurzweil (esp. 1987, 1993) and Kurzweil and Kocyan (2002), all floral development, Prychid et al. (2004: SiO₂ bodies), Yeung (2005: embryogeny), Rasmussen and Johansen (2006: fruits), Leitch et al. (2009: genome size, varies 168-fold), and Mayer et al. (2011: colleters, uncommon) For reticulate venation in Vanilloideae, see Cameron and Dickison (1998). For information on Orchidoideae, see Stern (1997a, b: anatomy), Stern et al. (1993a: anatomy), Pridgeon et al. (2001b, 2003: general), and Bell et al. (2009: nectar spurs), while for information on Epidendroideae, see Stern and Carlsward (2009: anatomy of Laeliinae), and Szlachetko (1995: general).

Phylogeny. Cameron (2007) provides a summary of phylogenetic studies on the family. There may still be some uncertainty over the position of Cypripedioideae. For instance, they may group (albeit weakly) with Vanilloideae (Freudenstein & Chase 2001) or be sister to Orchidaceae minus Apostasioideae, which would appear to make sense from the point of view of androecial evolution (Cameron et al. 1999, one gene, successive weighting). However, they may also be sister to Orchidaceae minus Apostasioideae and Vanilloideae (e.g. Kocyan et al. 2004; Cameron & Chase 2000; Cameron 2002, 2005b, 2006 [two genes; this study places them in a basal trichotomy in the family with atp alone]; Górniak et al. 2010 [nuclear gene Xdh]). This latter hypothesis is followed here, and it suggests that the monandrous condition may have evolved twice (see also Freudenstein et al. 2002, 2004). (A conservative topology might be that of a polytomy [as found by Cameron 2004].) Furthermore, there are suggestions that Codonorchis is either sister to [Epidendroideae + Orchidoideae] (e.g. Clements et al. 2002) or basal in Orchidoideae (Cameron 2006), and perhaps should be recognised as a subfamily, Codonorchidoideae (it has whorled leaves - see Cameron 2006) if in the former position (so cf. Jones et al. 2002).

For a phylogeny of Apostasioideae, see Kocyan et al. (2004). Relationships within Vanilloideae are becoming fairly well resolved (Cameron 2004, 2009; Cameron & Molina 2006; Pansarin et al. 2008). Included are Pogoniinae (Erythrorchis - mycoheterotroph), Vanillinae, and Galeolinae and Lecanorchidinae (both mycoheterotrophs); Bouetard et al. (2010) provide a phylogeny for Vanilla. For relationships in Cypripedioideae, including also a morphological survey, see Albert (1994); Li et al. (2011) provide a molecular phylogeny of Cypripedium, and find morphology sometimes to have misled over relationships in the past.

Orchidoideae include the erstwhile Spiranthoideae; there the anther is incumbent (as in Epidendroideae) and with apical rostellar tisssue. Relationships within Orchidoideae are becoming fairly well resolved (e.g. Cameron 2004); see also inda et al. (2010: cox1 intron). Górniak et al. (2006) discuss relationships in Spiranthinae, and Salazar et al. (2011) examined relationships around Dichromanthus et al. and find that adaptation to bird pollination has occured in parallel, confusing past generic limits. Clemens et al. (2002) clarify relationships of the Diuridae, a few of which are to be placed in Epidendroideae; for Codonorchis, see above. Disa is especially diverse in the Cape Region (see Bytebeier et al. 2007, 2008); for a phylogeny of Satyrium, see van der Niet and Linder (2008); it has diversified in the Fynbos region (Verboom et al. 2009). Prescottiinae s.l. have diversified at very high altitudes - to 4,900 m - in the Andes (Álvarez-Molina & Cameron 2009). For information about relationships in the speciose Caladenia, see Australian J. Bot. 57(4). 2009, for a study of Diuridae, Clements et al. (2002), of Pterostylis and relatives, see Clements et al. (2011), and for the African Disa (Disinae), see Bytebier et al. (2007).

For general phylogenetic relationships in Epidendroideae, see van den Berg (2005) and Górniak et al. (2010). Support for branching along the spine of Epidendroideae is not strong (e.g. Cameron et al. 1997; Pridgeon et al. 2001b; Cameron 2004). Palmorchis may be sister to Neottieae, the combined clade being in turn sister to all other Epidendroideae (Rothacker & Freudenstein 2006). It has been suggested that "basal" clades tend to lack articulated leaves, they have no velamen, and the pollinia are sectile (Pridgeon et al. 2005), and if so, this will affect identification of apomorphies for the subfamily. Malaxis and Liparis may not be monophyletic, but are closely intertwined; it is likely that they are secondarily terrestrial. Within Dendrobieae, Dendrobium is turning out to be polyphyletic (Yukawa & Uehara 1996 [orchids in this area are vegtatively variable, florally less so], Yukawa et al. 1993, 1996, 2000; Clements 2003 and earlier work, a mix of revisionary studies and phylogeny). The largely Old World Bulbophyllum is less studied, but the few (ca 60) New World species form a clade sister to the African taxa, the genus evolving in the general Southeast Asian region (Gravendeel et al. 2004; Smidt et al. 2011); Fischer et al. (2007) studied the Malagasy species. For a major study of Pleurothallidinae, see Pridgeon et al. (2001b); Pleurothallis itself is also not monophyletic; Abele et al. (2005) and Matuszkiewicz and Tukallo (2006) discuss the phylogeny of Masdevallia (Pleurothallidinae). Russell et al. (2010) discuss phylogeny in the widely-distributed Polystachya (Vandeae), where there is some correlation of polyploidy with wide species distributions. For phylogenetic relationships in Laeliinae, see van den Berg et al. (2000), for diversification in Coelogyninae, see Gravendeel et al. (2005), for studies in Maxillarieae, see Whitten et al. (2000), Williams and Whitten (2003), Sitko et al. (2006), and especially Whitten et al. (2007: Maxillaria to be restricted, generic realignments needed; Blanco et al. 2007: many new combinations) and Stern et al. (2004: anatomy), in Oncidiinae, Williams et al. (2001a, b, 2005), Stern and Carlsward (2006: anatomy), in Cymbidieae, Whitten et al. (2005), Cieślicka (2006: Eulophia), Neubig et al. (2008: Dichaea, Zygopetalinae), and Chase (1987), Chase and Palmer (1997), Williams et al. (2001), Chase et al. (2009) and especially Neubig et al. (2012) all focusing on Oncidiinae and the polyphyletic Oncidium, in Epidendreae (Kulak et al. 2006), in Sobralieae, Neubig et al. (2011), in angraecoid orchids in general, (Stewart et al. 2006), and in Aeridinae, see Hidayat et al. (2005).

Classification. Chase et al. (2003) provide a higher-level phylogenetic classification for the family, while Govaerts et al. (2003) is a provisional checklist of the family (see also World Checklist of Monocots). For useful accounts of Apostasioideae, see de Vogel (1969) and Pridgeon et al. (1999), Cypripedioideae, Pridgeon et al. (1999), Vanilloideae, Pridgeon et al. (2003), Orchidoideae, Pridgeon et al. (2001b, 2003), and Epidendroideae, Pridgeon et al. (2005, 2009). For an illustrated account of the genera, see Alrich and Higgins (2008).

Generic limits in the family are in the middle of a major overhaul to make them consistent with molecular findings, a considerable number of which have implications for clade/generic circumscriptions. It is now clear that there is widespread homoplasy in floral features (e.g. Waterman et al. 2009; Chase et al. 2009 and references), although in the past the importance of floral differences in separating genera has been over-emphasized. Thus the features characterising the erstwhile broadly-delimited and polyphyletic Oncidium - basically, mimicry of Malpighiaceae oil flowers - is just a single example (Williams et al. 2001; Neubig et al. 2008; especially Neubig et al. 2012). Szlachetko et al. (2005 and references) give a statement of the "floral" position, maintaining that variation in column form, etc., yields taxonomically important characters (see also Szlachetko 1995; Rutkowski et al. 2008). Clade limits suggested by molecular studies and those suggested by variation in floral morphology by no means always agree (Kocyan et al. 2008 and references), thus in Aeridinae there is probably widespread parallelism in floral characters used to delimit genera (Hidayat et al. 2005; see also Salazar et al. 2011 for similar examples). Note that it is not that floral morphology has nothing to say, but as in many other cases, undue reliance on it may lead us seriously astray if our interest is in reconstructing phylogeny. Indeed, in some cases, as in Epidendroideae, vegetative variation may correlate better with clades evident in molecular phylogenies (e.g. Cameron 2005a), even if some patterns of anatomical variation suggest little in the way of major phylogenetic structure (Stern et al. 2004; Stern & Carlsward 2006).

There have been extensive discussions about generic limits in European Orchidinae (Tyteca & Klein 2008, 2009; Bateman 2009; Scopece et al. 2010b). In an attempt to make generic limits there more objective, Scopece et al. (2010b) found that clade membership correlated well with post-zygotic reproductive isolation (embryo death). They suggested that a phylogeny-based classification in which this and other evidence was incorporated was preferable and could be defended on more explicit grounds, and this would allow morphologically distinctive taxa previously segregated as separate genera be incorporated taxonomically into their respective clades (Scopece et al. 2010b). This approach is somewhat reminiscent of that of Danser (1929), and although perhaps useful in Orchidaceae - it is going to be interesting to see how widely it can be applied there, and what the taxonomic consequences are - may be inapplicable to other angiosperms with different breeding behaviours.

Such disagreements reflect fundamental differences in classificatory philosophies and differing beliefs in the ability of morphology when used alone alone to disclose relationships. However, even having a phylogeny and agreeing over basic taxonomic philosophies does not mean that there will be automatic agreement about generic limits. Clements (2006 and references) suggested a wholesale pulverization and reorganization of Dendrobium and its relatives. However, the species numbers given above do not reflect this, and Burke et al. (2008), Janes and Duretto (2010), Schuitema and Adams (2011) and Adams (2011: focus on Australia) present an alternative view of how things should be reclassified; note that species limits are also at issue (Adams 2011). Jones and Clements (2002a, esp. 2002b) divide Pterostylis; since the monophyly of Pterostylis s.l. was confirmed, the division is perhaps questionable (if one likes broadly-drawn generic limits), and indeed Janes and Duretto (2010) and Jones et al. (2010) suggest returning to the old circumscription of the genus. However, Clements et al. (2011) note that there are nine or so identifiable groups around here... Jones et al. (2001) also dismember the monophyletic Caladenia and Clements et al. (2002) divide a monophyletic Corybas, as do Jones et al. (2002 - also much else). Such cases simply reflect conflicting preferences for narrow or broad genus limits, so they are something of a pain. In any event, in Australia, the result of nomenclatural changes made for these and other reasons is that about 45% of the species and subspecies in the entire orchid flora of some species have acquired new generic names in the brief period between 2000 and mid-2009 (Hopper 2009).

For an infrageneric classification of Vanilla, see Soto Arenas and Cribb (2010), and for an account of Anacamptis, Orchis, etc., see Kretzschmar et al. (2007). For a reclassification of Pleurothallidinae, see Pridgeon and Chase (2001); Pleurothallis was not monophyletic. There is some controversy about generic limits in the Masdevallia area, cf. Luer (2006) and Pridgeon (2007).

[[Boryaceae et al.] [[Ixoliriaceae + Tecophilaeaceae] [Doryanthaceae [Iridaceae [Xeronemaceae [Xanthorrhoeaceae [Amaryllidaceae + Asparagaceae]]]]]]]: (stem fructans +); cuticle wax crystals as parallel platelets; (T ± connate); (A inserted on T tube); seeds exotestal, (phytomelan +).

Chemistry, Morphology, etc. For the distribution of fructose oligosaccharides, see Pollard (1982) and Meier and Reid (1982). Although recorded there only for some Hypoxidaceae in the [Boryaceae [Blandfordiaceae [Lanariaceae [Asteliaceae + Hypoxidaceae]]]] clade, and not for some of the smaller families elsewhere in Asparagales, fructans seem to be widespread; they were not recorded from Orchidaceae.

[Boryaceae [Blandfordiaceae [Lanariaceae [Asteliaceae + Hypoxidaceae]]]]: septal nectaries external; ovules with hypostase; embryo sac with chalazal constriction, antipodal cells persistent.

Chemistry, Morphology, etc. For some information, see Kocyan and Birch (2011); there is extensive homoplasy in this little clade, so exactly where features like "septal nectaries external" are to be placed on the tree is unclear.

Phylogeny. Kocyan and Birch (2011: all genera studied) found that the last three families formed a tritomy.

BORYACEAE M. W. Chase, Rudall & Conran   Back to Asparagales

Plant xeromorphic; rhizome short, roots mycorrhizal; endodermis much thickened; leaves spiral, bundles with lateral phloem, base sheathing; inflorescence scapose, involucrate, raceme or spike; T tube short; A adnate to tube [not Alania]; anthers (centrifixed), little longer than wide; septal nectaries external; ovules many/carpel, micropyle bistomal; T persistent in fruit; (seed papillate - Borya); endosperm helobial, without starch, embryo small, ovoid; n = 11, 14; seedling?

2[list]/12. Australia, scattered (map: see Brittan et al. 1987). [Photo - Borya Habit © M. Fagg]

• Boryaceae are xeromorphic, some being resurrection plants, with aerial stems and stilt roots; the inflorescence is scapose and involucrate, but the flowers are undistinguished.

Evolution. Divergence & Distribution. Stem group Boryaceae are dated to ca 109 million years before present, crown group Boryaceae to ca 54 million years before present (Janssen & Bremer 2004: note their position).

Borya has tuberculate roots, perhaps with the coil-forming Rhizoctonia fungus is them (cf. Orchidaceae); the plant is arborescent and dessication-tolerant (e.g. Barthlott 2006).

Chemistry, Morphology, etc. The pedicels of Alania have several bracteoles. The nucellar tissue is a single cell layer across. Additional information is taken from Dahlgren et al. (1985), Conran (1998: general), Conran and Temby (2000: floral morphology).

[Blandfordiaceae [Lanariaceae [Asteliaceae + Hypoxidaceae]]]: ?

Phylogeny. An at most moderately well-supported - if persistently appearing - group (Rudall et al. 1998a; Chase et al. 2000a; Fay et al. 2000; Davis et al. 2004 - Lanariaceae not included; Graham et al. 2006; Chase et al. 2006; etc).

Chemistry, Morphology, etc. See Conran and Temby (2000) for general information esp. about ovules.

BLANDFORDIACEAE R. Dahlgren & Clifford   Back to Asparagales

Rhizome short; chemistry?; hairs 0; velamen +; raphides 0; leaves two-ranked, flat-curved, midrib prominent, sheath?; inflorescence a raceme; pedicels articulated; T large, tubular; A adnate to below middle of tube, latrorse, centrifixed, pollen trichotomosulcate; G stipitate, septal nectaries external, style short, stigma ± punctate, dry; ovules many/carpel, outer integument 3-4 cells across, nucellar cap ca 2 cells across, hypostase +; capsule septicidal; exotesta papillate; embryo short; n = 17, 27; cotyledon photosynthetic.

1[list]/4. E. Australia (map: see Brittan et al. 1987). [Photo - Blandfordia Flower © B. Walters]

Evolution. Divergence & Distribution. Stem Blandfordiaceae date to ca 100 million years before present (Janssen & Bremer 2004: note topology).

Chemistry, Morphology, etc. Information is taken from Clifford and Conran (1998: general), Di Fulvio and Cave (1965) and Prakash and Ramsey (2000: both embryology) and Kocyan and Endress (2001b: some floral morphology.

Previous Relationships. Rudall (2003a) suggested that there was a close morphological relationship between Boryaceae and Blandfordiaceae.

[Lanariaceae [Asteliaceae + Hypoxidaceae]]: hairs multicellular, often branched; stomata paracytic; lamina with distinct midrib; G ± inferior, septal nactaries internal; ovule with bistomal micropyle.

LANARIACEAE R. Dahlgren   Back to Asparagales

Plant with vertical rhizome; biflavones +; raphides 0 (styloids +); indumentum dendritic; leaves two-ranked to spiral, sheath ?closed; inflorescence branched; T connate half-way; A adnate in mouth; G ± inferior, style long, stigma punctate; ovules 2/carpel, apotropous, micropyle zig-zag, outer integument 5-7 cells across, parietal tissue ca 3 cells across, nucellar cap 2-3 crells across, obturator +; capsule type?; seed 1; exotesta palisade, other cells rounded, tegmen persists, develops at micropyle; endosperm initially with starch; n = 18; seedling?

1[list]/1: Lanaria plumosa. Cape Province, South Africa. [Photo - Habit] [Photo - Habit.]

• Lanariaceae are monocots that can be recognised by their shortly branched inflorescences covered by dendritic hairs and radially symmetric flowers with tepals connate half-way.

Evolution. Divergence & Distribution. The divergence of stem Lanariaceae dates from ca 113 million years before present (Janssen & Bremer 2004: note topology).

Chemistry, Morphology, etc. Information is taken from De Vos (1963 - embryology), Dora and Edwards (1991 - chemistry) and Rudall (1998 - general).

[Asteliaceae + Hypoxidaceae]: rosette-forming or caespitose; flavonols +; mucilage canals +; endosperm thin-walled; cotyledon not photosynthetic, ligule long.

ASTELIACEAE Dumortier   Back to Asparagales

Plant ± rhizomatous; saponins +; indumentum leipdote-stellate; leaves spiral, base sheathing or not; plant dioecious (flowers perfect), inflorescence branched raceme or spike, inflorescence bracts large; flowers rather small, T connate basally (free); A adnate to base of T/free; (G subinferior; placentation parietal), intra-ovarian trichomes +, style divided or not (short), stigmas dry; ovules few to many/carpel, micropyle also zig-zag; fruit a berry; (seed with mucilaginous hairs), endosperm oily, no hemicellulose; n = 8, 30, ?35, chromosomes 4-6 µm long; seedling primary root well developed.

1[list]/36. New Zealand to New Guinea, Pacific Islands E. to Hawaii, Chile, the Mascarenes (map: see van Steenis & van Balgooy 1966; Brittan et al. 1987). [Photos - Milligania & Astelia Flowers © C. Howells - Australian Plants Society, Tasmania.]

Evolution. Divergence & Distribution. Stem group Asteliaceae are dated to ca 104 million years before present, crown group Asteliaceae to ca 92 million years before present (Janssen & Bremer 2004: note topology). For the biogeography of the family, especially Astelia, see Birch et al. (2008, 2011: summaries).

Given the developing ideas of relationships in the family (see below), character evolution in it will repay investigation.

Chemistry, Morphology, etc. The nectaries may be on the outside of the ovary. For additional information, see Prakash and Ramsey (2000: embryology), and Bayer et al. (1998a: general) for information.

Phylogeny. the phylogeny of the family has been clarified by Birch et al. (2009); Milligania, with loculical capsular fruits, a semi-inferior ovary and no intra-ovarian trichomes, perfect flowers, etc., and often considered rather different from other Asteliaceae, seems to be embedded in Astelia, as do the other small genera previously recognized in the family (Birch et al. 2008, esp. 2009).

Previous Relationships. Relationships between Milligania and Lanaria and Blandfordia (see families immediately above) have been suggested (Bayer et al. 1998a).

HYPOXIDACEAE R. Brown, nom. cons.   Back to Asparagales

Stem ± cormose to rhizomatous, leaf bases persisting, contractile roots common; saponins 0; velamen +, dimorphic root hypodermis 0; stomata (tetracytic), with oblique or parallel cell divisions; leaves 3-ranked, (vernation conduplicate-)plicate (conduplicate-flat), (unifacial), sheaths also closed; inflorescence various, scapose, axis compressed; (flowers 2-merous), T free to tubular, (A inserted lower down; many; 3, plus 3 staminodes adnate to style = gynostemium - Pauridia; extrorse), (basi- or centrifixed, sagittate); tapetum plasmodial, microsporogenesis successive [tetrads tetragonal]; (pollen to trisulcate, inaperturate); ovary inferior, (apical beak +), septal nectaries 0, (placentation parietal - Empodium), stigmas commissural, ± 3-radiate, dry or wet; ovules few to many/carpel, apotropous, (micropyle zigzag), nucellar cap (0) 2-3 cells across; fruit dehiscing laterally, (circumscissile), or baccate; seeds globose, (strophiole +); exotesta palisade or not, (endotegmen persistent), raphe prominent; endosperm nuclear [Pauridia]; n = 6-9, 11, chromosomes 2-5 µm long; embryo short, ± undifferentiated.

7-9[list]/100-220: Hypoxis (50-100). Seasonal tropics, esp. southern Africa (temperate) (map: see Fl. N. Am. 26: 2002; FloraBase vii.2005). [Photo - Inflorescence] [Photo - Flower]

• Hypoxidaceae can be recognised by their rosettes of plicate or at least folded leaves and persistent leaf bases; non-glandular indumentum is quite prominent. In the flowers, the outer whorl of tepals tends to be green outside and the ovary is inferior; there is often a narrowly tubular part at the apex of the ovary formed by the connate tepals or by an apical beak of the ovary itself.

Evolution. Divergence & Distribution. Stem group Hypoxidaceae are dated to ca 78 million years before present, crown group Hypoxidaceae to ca 100 million years before present (Janssen & Bremer 2004).

Floral Biology & Seed Dispersal. For a summary of information about what is known about pollination in the family - pollen is the main reward, and flies of various kinds, beetles and bees seem to be the pollinators - see Kocyan et al. (2011). The rostrum, a narrowed apical beaked portion of the ovary, appears to have evolved more than once, but its function is uncertain. At least some species of Hypoxis are apomictic (Nordal 1998).

Chemistry, Morphology, etc. Kocyan (2007) found that some flowers of Curculigo racemosa were polyandrous, however, the stamens were not fasciculate. The staminodes of Pauridia that are adnate to the style perhaps rather surprisingly appear to represent the outer androecial whorl - and they are also responsible for reports of a 6-lobed stigma in the family.

There is controversy over the tapetum type in the family and in the numbers of nuclei in the cells, and whether or not there is a velamen in the root. The ovules have a parietal cell, so are not tenuinucellate [?incorrect - not in the literature I have read]. The endosperm is reported as being nuclear or helobial; if the former, then the antipodal cells tend to persist (de Vos 1948, 1949).

Some information is taken from de Vos (1948, 1949: ovule and seed), Thompson (1976: vegetative; 1978 floral morphology), Rudall et al. (1998a: anatomy), Nordal (1998: general), Judd (2000 general), Kocyan and Endress (2001b: floral morphology), and Wiland-Szymanska (2009: general, east Africa).

Phylogeny. Kocyan et al. (2011) recovered three main clades - Curculigo et al., Pauridia et al., and Hypoxis - in the family, a slight modification of the results obtained by Rudall et al. (1998). Relationships between these clades was unclear.

Classification. For generic limits, see Kocyan et al. (2011).

Previous Relationships.Rudall (2003a) suggested that there might be a close morphological relationship between Hypoxidaceae and Orchidaceae. In older classifications, Hypoxidaceae were included in Amaryllidaceae.

[[Ixoliriaceae + Tecophilaeaceae] [Doryanthaceae [Iridaceae [Xeronemataceae [Xanthorrhoeaceae [Amaryllidaceae + Asparagaceae]]]]]]: ?

Evolution. Divergence & Distribution. The divergence of this clade (i.e. [Asparagaceae + Iridaceae + Cyanastraceae (= Tecophilaeaceae)]) has been dated to ca 84 million years before present (Eguiarte 1995).

Phylogeny. This clade is strongly supported in analyses using data from four plastid genes (Fay et al. 2000; see also Chase et al. 2000a; Soltis et al. 2007a), but no morphological characters have yet been found for it. The positions of [Ixoliriaceae + Tecophilaeaceae] and Doryanthaceae are reversed in Kim et al. 2011).

[Ixioliriaceae + Tecophilaeaceae]: cormose; leaves spiral, base sheathing; flowers quite large; outer T mucronate to aristate, T tube short; A inserted at mouth of tube; embryo long; x = 12.

Chemistry, Morphology, etc. The outer tepals in at least some Iridaceae (and Orchidaceae!) are also mucronate to aristate.

Phylogeny. There is weak to moderate support for this sister-taxon pair in Chase et al. (2000a), Pires et al. (2006) and Givnish et al. (2006) and stronger support in Graham et al. (2006, but poor sampling); they have a very long branch in the three-gene analysis of Fay et al. (2000). Davis et al. (2004) found some support for a sister-group relationship between Ixoliriaceae and Iridaceae, although sampling was poor; Chase et al. (2006) find strong support for this relationship. Janssen and Bremer (2004) showed Ixoliriaceae diverging considerably before (although adjacent to) Tecophilaeaceae.... All told, their position is somewhat unclear, and they sometimes link with [Ixoliriaceae + Iridaceae] being sister to Doryanthaceae in Chase et al. (2006: very little support), which are adjacent on the tree here.

Previous Relationships. Ixioliriaceae and Tecophilaeaceae are placed together (along with Eriospermaceae and Lanariaceae - for the former, see Ruscaceae s. str, Asparagaceae s.l.) in Takhtajan (1997).

IXIOLIRIACEAE Nakai   Back to Asparagales

Plant a tunicated corm; saponins 0?; dimorphic exodermis 0; peduncle with a sclerenchymatous ring; mucilage cells +; leaf shortly cylindrical at apex, base ?type; inflorescence terminal, subumbellate, leafy; T tube short; A centrifixed; ovary inferior, stigma 3-lobed, dry; ovules many/carpel; seeds angled, phytomelan +; endosperm walls pitted, starch in cells surrounding embryo; cotyledon remains white even when exposed to light!

1[list]/3. Egypt to Central Asia (map: from Traub 1942, rather approximate). [Photo - Flower © A. Shoob]

• Ixoliriaceae are cormose herbs with racemosely-arranged and quite large blue, shortly tubular flowers with an inferior ovary.

Evolution. Divergence & Distribution. The divergence of the Ixoliriaceae clade is dated to ca 112 million years before present (Janssen & Bremer 2004).

Chemistry, Morphology, etc. Vascular bundles in the leaf are unequal in size, some in the inflorescence axis are arranged in a circle, enclosing additional scattered bundles. The inflorescence axis is leafy, the flowers are blue and there are no alkaloids, all unusual features for Amaryllidaceae, where Ixiolirion was often included.

Information is taken from Arroyo (1982) and Arroyo and Cutler (1984: both anatomy), and also from Kubitzki (1998b: general) and DÖnmez and Isik (2008); see Tillich (2003) for seedling morphology.

Previous Relationships. Both Dahlgren et al. (1985) and Takhtajan (1997) recognised relationships between Ixoliriaceae Tecophilaeaceae, as well as with a selection of other asparagalean families.

TECOPHILAEACEAE Leybold, nom. cons.   Back to Asparagales

Corm tunicate or not; ?saponins +; stomata variable; (leaves petiolate, with midrib), sheaths open? (none); inflorescence a raceme, branched or not, or flowers axillary; flowers often monosymmetric; (T tube moderately long); (stamens of very different sizes), (stamens 4-3, staminodes 2-3), anthers dehiscing ± by pores; pollen operculate (not Kabayea and Cyanastrum); (G semi-inferior; carpels free - Cyanastrum), stigma punctate; ovules 2-many/carpel, ana-campylotropous, outer integument "thick", vascularized [Cyanastrum], obturator +; seed (one/fruit), variable, phytomelan +/0, testa multilayered, (exotesta palisade), thick-walled; endosperm (nuclear - Cyanella), thick-walled, pitted or not, (± absent), ?starch (0, chalazosperm + - Cyanastrum), embryo also short; n = 8, 10-12, 14, chromosomes 2-4 µm long; cotyledon not photosynthetic, (coleoptile +), primary root long (hypocotyl and primary root 0 - Cyanastrum).

9[list]/23. Africa, Chile, and U.S.A. (California - Odontostomum) (map: from Carter 1962; Scott 1991; Brummitt et al. 1998; Fl. N. Am. 26: 2002).[Photo - Flower, Flower.]

• Tecophilaeaceae are cormose herbs sometimes with broad-bladed, petiolate leaves; their flowers have spreading tepals and are monosymmetric because of the androecium, the stamens being strongly dimorphic. The anthers open by pores.

Evolution. Divergence & Distribution. The divergence of the Tecophilaeaceae clade is dated to ca 108 million years before present, and of the crown group to ca 87 million years before present (Janssen & Bremer 2004).

Chemistry, Morphology, etc. Cells adjacent to stomata in Cyanastrum were described as having parallel cell divisions by Tomlinson (1974). The monosymmetry of the flower is largely caused by the androecium; enantiostyly also occurs in a few species of Cyanella. Odontostomum has been reported as having six staminodia alternating with the six stamens; these are more properly to be described as a corona or enations.

Some information is taken from Rudall (1997), Simpson and Rudall (1998) and Brummitt et al. (1998), that on ovules, from Nietsch (1941), and that on seedlings, which are variable in their morphology, from Tillich (1995, 2003).

Synonymy: Androsynaceae Salisbury, Conantheraceae Pfeiffer, Cyanastraceae Engler, Cyanellaceae Salisbury, Walleriaceae Takhtajan

[Doryanthaceae [Iridaceae [Xeronemataceae [Xanthorrhoeaceae [Amaryllidaceae + Asparagaceae]]]]]: ?

Evolution. Divergence & Distribution. Pollen fossils assignable to Iridaceae-Isophysis or to Doryanthes have been found in Late Cretaceous rocks ca 75-70 million years of age from Eastern Siberia (Hoffmann & Zetter 2010). Doryanthaceae stem node ages have been astimated at ca 107 million years (Jansen & Bremer 2004), while the separation of Doryanthaceae from Iridaceae (sic) has been estimated at ca 82 million years (Goldblatt et al. 2008).

Phylogeny. Doryanthaceae may go around here; although there is only moderate support in Fay et al. (2000), there is 92% bootstrap support for a sister group relationship [Doryanthaceae + other Asparagales] in Graham et al. (2006: note sampling).

DORYANTHACEAE R. Dahlgren & Clifford   Back to Asparagales

Huge sub-bulbous tufted perennial; steroidal saponins +; vascular bundles encased in fibres; styloids +, raphides 0; cuticular wax rodlets parallel, stomata paracytic, subsidiary cells with oblique divisions; leaves spiral, when older with dry threads at apex; inflorescence a thyrse; T large, tube long; (A also adnate to the base of the tepal lobes), anthers latrorse, centrifixed, endothecium thick; tapetal cells with several nuclei; pollen trichotomosulcate, surface reticulate; ovary inferior, stigma punctate, dry; ovules many/carpel, outer integument ca 5 cells across, inner 2, parietal tissue ca 5 cells across, nucellar cap ca 2 cells across, postament +; antipodal cells to 5, ± persistent; seeds flattened, winged; testa multiplicative, many-layered, with phlobaphene; endosperm helobial, thin-walled, embryo flattened; n = 17, 18, 22, 24, bimodal; seedling with laterally compressed haustorium, coleoptile +.

1[list]/2. E. Australia (map: from O. Seberg, pers. comm). [Photo - Habit.]

• Doryanthaceae are massive, tufted, perennial monocots; the leaves have entire margins although they disintegrate into fibres at the apex. Their subumbellate inflorescences borne at the end of long (to 6 meters), unbranched, leafy stems have numerous large, radially symmetrical, bright red flowers with inferior ovaries.

Chemistry, Morphology, etc. Much information is taken from Wunderlich (1950) and Clifford (1998); Blunden et al. (1973) described leaf anatomy, and Tillich (2003) described seedling morphology. Kocyan and Endress (2001b) note that the connective is massive, each stamen being supplied by 2-4 "vascular complexes", although these were not observed by Newman (1928, 1929). There may be a hypostase immediately beneath the embryo sac, although there is also a great amount of tissue between it and the chalazal bundle (Newman 1928).

Previous Relationships. Rudall (2003a) suggested that there was a close morphological relationship between Iridaceae and Doryanthaceae.

Iridaceae [Xeronemataceae [Xanthorrhoeaceae [Amaryllidaceae + Asparagaceae]]]: (vegetative fructans, glucomannans +); (stem secondary growth +); (seeds with glucomannans as reserves); Arabidopsis-type telomeres lost, (TTAGGG)_n [human-type telomeres] common.

Chemistry, Morphology, etc. A distinctive pattern of secondary growth is scattered through this clade. A meristem cuts off tissue to the inside in which separate vascular bundles embedded in ground tissue differentiate; this type of secondary thickening is scattered in Asparagales (Rudall 1991, 1995b for records and literature; not that it has recently been reported from Eriocaulaceae (Poales: Scatena et al. 2005). Apparently there are only tracheids in the xylary tissue (Fahn 1990). Mangin (1882) suggested there might be a connection between the origin of this secondary thickening and the reticulum of vascular bundles in association with which "adventitious" roots arise in monocots.

Glucomannan seed reserves are reported from at least some members of this clade - Iridaceae, Asparagaceae-Asparagoideae and -Scilloideae-Ornithogaleae - and they are also known from some Liliales; the vegetative plants also may have distinctive carbohydrates (Jakimow-Barras 1973; Meier & Reid 1982; Buckeridge et al. 2000).

Note that the loss of Arabidopsis-type telomeres is not simple; human-type telomeres ((TTAGGG)_n)) may predominate, but there are other types, too. Asparagaceae-Scilloideae agree with other members of this clade, although the Arabidopsis-type telomere is somewhat more common than in the other members sampled (Adams et al. 2001; especially Sýkorová et al. 2003b, 2006a, b). Acanthocarpus also lacks the telomere, alone among the taxa discussed there as being out-groups; in fact it is a member of Asparagaceae-Lomandroideae (ex Laxmanniaceae), an ingroup, not Dasypogonaceae, which is a commelinid.

Phylogeny. A group with quite strong support in Fay et al. (2000) and Soltis et al. (2007a), etc.

IRIDACEAE Jussieu, nom. cons.   Back to Asparagales

Plant rhizomatous; roots mycorrhizal, root hairs 0; flavone C-glycosides, flavonols +, chelidonic acid 0?; dimorphic root hypodermis +; (stem endodermis +); raphides 0, styloids +; cuticular wax rodlets parallel; leaves two-ranked, often equitant and isobifacial [oriented edge on to the stem], vernation plicate; flowers usu. large; T ± free, apex often aristate; A 3 (2 - Diplarrhena), extrorse; style branched (branches bifid), stigma on the edges of the complex/expanded style, dry; ovules 1-many /carpel, micropyle endo- or exostomal, outer integument 4-6 cells across, parietal tissue absent or 1(-2) cells across; seed testal and tegmic, phytomelan 0, phlobaphene +, endotesta with lipids; endosperm thick-walled, hemicellulosic, embryo quite large; cotyledon not photosynthetic, (with ligule or coleoptile - e.g. Tigridia; photosynthetic - e.g. Sisyrinchium; hypocotyl short).

66[list]/2025 - eight subfamilies below. World-wide (map: see Heywood 1978 [S. America], Hultén & Fries 1986; Mathew 1989; Fl. N. Am. 26: 2002; Bahali et al. 2004; FloraBase 2005; Davies et al. 2005; Rodrigues & Sytsma 2006; Alexeyeva 2008. Note that Fig. 2b in Davies et al. 2005 suggests that Iridaceae grow throughout Africa, much of the Arabian Peninsula, etc. - this should be confirmed). [Photos - Collection]

1. Isophysidoideae Thorne & Reveal

Vessel elements in roots with scalariform perforation plates; biflavonoids [amentoflavone] +; flower solitary, with spathes; microsporogenesis?; G [3], septal nectary 0, style shortly branched, branches alternating with anthers; seedling unknown.

1/1: Isophysis tasmanica. Tasmania.

Synonymy: Isophysidaceae F. A. Barkley

[Iridoideae [Patersonioideae [Geosiridoideae [Aristeoideae [Nivenioideae + Crocoideae]]]]]: xanthone [mangiferin] +; vessel elements in roots with simple perforation plates; inflorescence with cymose units in which the flowers arise successively from axils of the prophylls, i.e. alternating [= a rhipidium]; flowers short lived [open ca 1 day]; (pollen operculate [often with two exine bands in a sulcus]); G inferior; endosperm nuclear.

2. Iridoideae Eaton

(Plant bulbous); gamma-glutamyl peptides, metacarboxy amino acids +; vessel elements in root with simple perforation plates; rhiphidia simple; (flowers long-lived; monosymmetric - Diplarrhena); T nectaries +, (oil glands or oil hairs +); anther endothecium with spiral thickenings; (pollen grains with encircling aperture); (septal nectaries + - Diplarrhena), style branches long, tubular, (branches alternating with anthers, Sisyrynchium et al.); n = ?.

30/820: Iris (280, inc. Belamcanda), Moraea (200), Sisyrinchium (60), Tigridia (50). Worldwide, but esp. the spine of Central and South America.

[Patersonioideae [Geosiridoideae [Aristeoideae [Nivenioideae + Crocoideae]]]]: rhipidia 2, fused [binate], each unit with 2-many flowers; T connate; endothecium with base-plate or U-shaped thickenings; extra codon in rps4 gene.

3. Patersonioideae Goldblatt

Plant ± woody and rhizomatous; biflavonoids [amentoflavone] +; vessel elements in roots often with scalariform perforation plates; secondary thickening +; flowers blue, (inner tepals reduced to scales or 0); filaments ± connate; pollen spherical, inaperturate, intectate; septal nectary 0; embryo small; n = 11, 21; two extra codons in rps4 gene.

1/21. More or less open conditions, scattered in Sumatra, Borneo, New Guinea, New Caledonia, and the periphery of Australia (map: from George 1986).

[Geosiridoideae [Aristeoideae [Nivenioideae + Crocoideae]]]: ?

4. Geosiridoideae ("Geosiridaceae") Goldblatt & Manning

Echlorophyllous, saprophytic; leaves heterobifacial; flowers sessile; T connate basally only; microsporogenesis successive; septal nectary 0; seeds minute, dust-like; endosperm helobial, starchy; n = ?

1/2. Madagascar, the Comores.

[Aristeoideae [Nivenioideae + Crocoideae]]: ?

5. Aristeoideae Vines

Plumbagin +; vessel elements in roots often with scalariform perforation plates; flowers ± blue; T connate basally only; septal nectay 0; embryo small; n = 16.

1/55. More or less open conditions, sub-Saharan Africa and Madagascar.

[Nivenioideae + Crocoideae]: flowers long-lived.

6. Nivenioideae Goldblatt

Plant with woody caudex; secondary thickening +; unit of rhipidium with 1-2 flowers; P long-tubular; (pollen grains with encircling sulcus); 1(-4) shield-shaped [tangentially flattened] seeds per loculus; n = 16.

3/14. Restricted to the S.W. Cape region, South Africa

6. Crocoideae G. T. Burnett

Plant with corms; vessel elements in root with simple perforation plates; leaves when plane with pseudomidrib (not Pillansia), sheath closed; inflorescence spicate; rhipidium binate, with a single flower, pedicel 0; (flowers short-lived), variously monosymmetric (polysymmetric); anther endothecium with spiral thickenings; pollen exine tectate, perforate-scabrate, aperture with one or a pair of longitudinal bands forming operculum, (zona-aperturate); septal nectaries +/0; ovules campylotropous, hypostase prominent, postament +; n = 9-17.

28/995: Gladiolus (260), Romulea (90), Geissorhiza (85), Crocus (90), Hesperantha (80), Babiana (55), Watsonia (50), Ixia (50). Overwhelmingly southern African, to Europe, Madagascar and Central Asia.

Synonymy: Crocaceae Vest, Galaxiaceae Rafinesque, Geosiridaceae Jonker, Gladiolaceae Rafinesque, Ixiaceae Horaninow

• Iridaceae may be recognised by their usually ensiform, equitant, isobifacial leaves and their large flowers with showy tepals, three extrorse stamens, complex stigma, and inferior ovary.

Evolution. Divergence & Distribution. Pollen fossils assignable to Iridaceae-Isophysis or to Doryanthes have been found in Late Cretaceous rocks ca 75-70 million years of age from Eastern Siberia (Hoffmann & Zetter 2010). The separation of Doryanthaceae from Iridaceae (sic) has been estimated at ca 82 million years (Goldblatt et al. 2008), while stem group Iridaceae are dated to ca 103 million years before present, divergence of crown group Iridaceae to ca 96 million years before present (Janssen & Bremer 2004: Isophysis was included).

Davies et al. (2005) discuss diversification rates within the family, finding them to be notably diverse (i.e. having clades with a disproportionate number of species) in e.g. southern Africa, but relatively less so in the north temperate zone. Iridaceae are one of the major geophytic groups of the Cape (Procheŝ et al. 2006) with more than 650 species there; Davies et al. (2004c) see this diversification as the result of the interaction of local features such as traits affecting reproductive isolation and the ecological and climatic heterogeneity of the area. For the radiation of the Cape genus Moraea, both cytologically and florally diverse, see Goldblatt et al. (2002); radiation in this and other iridaceous Cape genera may have begun in the fynbos in the Miocene some 25 million years before present, divergence in the succulent Karoo being more recent (Verboom et al. 2009). Schnitzler et al. (2011) suggest that diversification of two geophytic Cape genera, Babiana, with ca 92 species nearly all from the Greater Cape floristic region, and Moraea, with over 150 species in Cape region, is in part connected with soil type preferences changing during speciation, clade diversification beginning a mere 15-17 million years ago in the mid-Pliocene; diversification rates in the Cape region and outside are largely similar (Silvestro et al. 2011).

Floral Biology & Seed Dispersal. Iridaceae show considerable floral diversification, whether based on the flower type of Iris et al. or on the tubular flowers such as occur in Gladiolus et al. (e.g. Bernhardt & Goldblatt 2006 and references; Rodrigues & Sytsma 2006; Wilson 2006). In Iris and its relatives, the tepaloid style overarches the stamen opposite it, the landing platform being a member of the outer perianth whorl. Thus the flower is a kind of revolver flower, with three points of entry for the pollinator - another way of thinking about the flower is that it appears to the pollinator as if were really three monosymmetric flowers. Interestingly, in the oil-flowers of Cypella the three landing platforms for the pollinating bee are members of the inner perianth whorl. Here the pollen deposited on the backs of the bees comes from half anthers of adjacent stamens and is deposited on the receptive surfaces of two adjacent half-stigmas (Vogel 1974). There are other oil flowers in Iridaceae, thus oil-secreting trichomes appear to have evolved twice on flowers in the speciose Sisyrinchium (Chauveau et al. 2011).

The flowers of Gladiolus are obliquely monosymmetrical, although this is hardly apparent in the open flowers due to changes in orientation as the flower and inflorescence grow. Tepal patterning, where it occurs, is usually on an adaxial lateral member of the outer whorl and adjacent members of the inner tepal whorl and is then clearly on the adaxial side of the flower, but it sometimes occurs on the adaxial lateral and abaxial members of the outer whorl and the member of the inner whorl between them (Eichler 1875; Choob 2001). Although it is likely that other Crocoideae show the same oblique monosymmetry, monosymmetry in Diplarrhena (Iridoideae) appears to be vertical; that genus has only two stamens and one staminode. Interesting infraspecific variation occurs, thus in some flowers of Crocosmia X crocosmiiflora it was observed that the odd member of the outer whorl was adaxial while in others it was abaxial; the patterning of the tepals, etc., varied accordingly. All told, well over half the family has monosymmetric flowers of one sort or another, and the evolution of monosymmetry in the family will repay further study (see also Davies et al. 2004b).

Much work has been carried out on pollination in Iridaceae, particularly those from the sub-Saharan (esp. South African) region (Goldblatt and Manning 2006, see also 2008 for a general account). Babiana (Crocoideae) is pollinated by birds, scarab beetles, bees, moths, etc. (Bernhardt & Goldblatt 2006, esp. Goldblatt & Manning 2007), while scarabeid monkey beetles pollinate the flowers of three Cape genera of Iridaceae that have distinctive dark markings (van Kleunen et al. 2007). Oil flowers are found in the ca 35 species of Sisyrinchium from South America and also in some other New World Iridoideae like Tigridia (Renner & Schaefer 2010).

Vegetative Variation. There is considerable variation in vegetative morphology in the family, some taxa having terete, unifacial leaves, others apparently ordinary heterobifacial leaves (even some Iris), etc., and many have ensiform isobifacial leaves, as in Gladiolus, most Iris, etc. (e.g. Arber 1925); Geissorhiza alone has ligulate leaves. Crocus has revolute leaves with a unifacial midrib, and Romulea seems to be a modification of this. Some taxa are more or less woody, and secondary thickening has been reported from them; the vessel elements in their roots often have scalariform perforation plates (Cheadle 1964: inc. Klattia). For the water-catching leaves with very distinctive morphologies that are found especially in taxa from Namaqualand, see Vogel and Müller-Doblies (2011).

Chemistry, Morphology, etc. For the occurrence of plumbagin in Aristea, see Harborne and Williams (2001). Homeria and Moraea (Iridoideae) have bufadienolides (Harborne & Williams 2001). Iris contains a greater diversity of isoflavonoids than any other group outside Fabaceae (Reynaud et al. 2005); for xanthones, especially in Iris, see Williams et al. (1997b).

Goldblatt (1990) interpreted the paired "bracts" below the single flowers of Isophysis as representing a reduced rhipidium - a rhipidium may then be another synapomorphy for the family. Some species of Nivenia are heterostylous, a very uncommon condition in the monocots. Aristea is palynologically very variable, some members even having disulcate pollen (see Goldblatt & Le Thomas 1997; le Thomas et al. 2001). In Sisyrynchium and its relatives the style branches alternate with the stamens; elsewhere in the family, the two are on the same radius. For a discussion of the caruncles/arils of Iris, see Wilson (2006).

Additional information is taken from from Mathew (1989: Iris in the old sense and its relatives), Rudall et al. (1986) and Rudall (1995a), both anatomy, Goldblatt et al. (1998: general), Goldblatt (2001: general), Wilson (2001: embryology of Iris), Cocucci and Vogel (2001: nectaries), Tillich (2003a: seedlings - very variable), Rudall et al. (2003a: nectary evolution), DÖnmez and Isik (2008: pollen), and Goldblatt and Manning (2008: general account).

Phylogeny. Iridaceae are monophyletic in nearly all studies (but cf. Chase et al. 1995a). Initial resuls suggested that the monotypic Isophysidoideae were sister to the rest of the family, Crocoideae and Iridoideae appeared to be monophyletic, but the status of Aristeoideae was unclear. The four-gene analysis of Reeves et al. (2001a, b) suggested that Patersonia, Geosiris, and Aristea were successively sister to a large clade making up [Aristeoideae + Crocoideae]; support was mostly moderate (see also Teixeira de Souza-Chies et al. 1997). If these relationships are confirmed, either the circumscription of Crocoideae will have to be considerably extended, or three more subfamilies will be needed - basically, the classification that developed. Goldblatt et al. (2008: five plastid genes) opted for this latter classification; they found strong support for the pectinations basal to Crocoideae s. str., albeit using successive weighting, which tends to leave one a little uneasy. Within Crocoideae the five tribes are mostly only moderately supported and their relationships are unresolved, on the other hand, the five tribes recognised in Iridioideae are well supported and their relationships are better resolved: [Diplarreneae [Irideae [Sisyrincheae [Trimezieae + Tigridieae]]]] (Goldblatt & Manning 2008; seee also Golblatt et al. 2004, 2006).

Note that the Australian Diplarrhena, whose flowers have only two stamens and are monosymmetric, is perhaps sister to all other Iridoideae (Reeves et al. 2001a, b; Rudall et al. 2003a); Diplarrhena also has spherical, inaperturate, intectate pollen grains. For diversification of the American Tigridieae, see Rodrigues and Sytsma (2006); there is very extensive floral homoplasy (as in Iris - Wilson 2006). For a phylogeny of Iris, see Tillie et al. (2001) and Wilson (2004); there is phylogenetic resolution of the major groups in the genus (Wilson 2011). Chauveau et al. (2011) discuss the phylogeny of Sisyrinchium. Within Crocoideae Tritoniopsis, with a tubular cotyledonary sheath and tubular cataphyll, may be sister to the rest of the subfamily, but with at best moderate support (Goldblatt et al. 2006; Golblatt & Manning 2008). For a phylogeny of Crocus see Petersen et al. (2008, cf. in part Frello et al. 2004), and this is explained by Mathew et al. (2009); see Goldblatt and Manning (1998) for a treatment of much of Gladiolus.

Classification. I follow the classification suggested by Goldblatt et al. (2008); the subfamilies are for the most part well characterised. See Goldblatt and Manning (2008) for an account of the genera and Wilson (2011) for an infrageneric classification of Iris.

Xeronemataceae [Xanthorrhoeaceae [Amaryllidaceae + Asparagaceae]]: mitochondrial rpl2 gene lost.

Phylogeny. This is a strongly supported group in Fay et al. (2000) and Soltis et al. (2007a). The loss of the mitochondrial rpl2 gene occurs either at this node or the next up the tree, according to its distribution in Adams et al. (2002b).

XERONEMATACEAE M. W. Chase, Rudall & Fay   Back to Asparagales

Plant rhizomatous; leaves two-ranked, equitant and isobifacial [oriented edge on to the stem]; inflorescence a dense spike; flower large; pollen boat-shaped; style solid; n = 17, 18.

1/2. New Zealand (Poor Knights Island) and New Caledonia.

• Xeronemataceae are large monocot herbs that may be recognised by their equitant isobifacial leaves and congested inflorescences with rather large, radially symmetrical, upwardly-facing flowers. The stamens are strongly exserted.

Evolution. Divergence & Distribution. The divergence of Xeronemataceae from other Asparagales has been dated to ca 100 million years before present (Janssen & Bremer 2004).

Chemistry, Morphology, etc. The family is little known, although there is some information in Chase et al. (2000c); the style is scored as if it is hollow in Rudall (2003a).

Previous Relationships. Xeronemataceae were provisionally placed in Asphodelaceae by Takhtajan (1997) and in Hemerocallidaceae by Clifford et al. (1998).

Xanthorrhoeaceae [Amaryllidaceae + Asparagaceae]: (pedicels articulated); septal nectaries infralocular [see beginning of this page]; ovary superior; ovules with parietal tissue 2-3 cells across.

Chemistry, Morphology. For chromosome sizes of a number of taxa in the group, see Vijayavalli and Mathew (1990 - as Liliaceae). Schnarf and Wunderlich (1939) provide some embryological details and El-Hamidi (1952) some for the gynoecium from scattered taxa in "Asphodeloideae"; the latter found substantial similarity between all the taxa he examined except Aphyllanthes.

Phylogeny. This group has strong support in Fay et al. (2000) and Chase et al. (2000b). The optimisation of successive microsporogenesis on the tree is uncertain, i.a. microsporogenesis varies within Xanthorrhoeaceae.

XANTHORRHOEACEAE Dumortier, nom. cons.   Back to Asparagales

Anthraquinones +; (vessel elements in roots with simple perforation plates0; styloids +; (stomata paracytic, subsidiary cells with oblique divisions); inflorescence branches cymose; outer integument >3 cells across, hypostase +; cotyledon not photosynthetic.

35/900. Esp. Old World, not Arctic, western South America.

1. Hemerocallidoideae Lindley

Habit various; flavonols, naphthoquinones, saponins +; roots often swollen; (vessels in the stem); mucilage cells 0; raphides 0; cuticular wax rodlets parallel; leaves (spirally) two-ranked, vernation conduplicate to flat-conduplicate, sheath closed, (immediately above the sheath semi-ensiform, unifacial - most of phormioid clade); inflorescence various; (bracteoles lateral), pedicel usu. articulated, (flowers monosymmetric); (median tepal of outer whorl adaxial - Hemerocallis), T tube short (1/2 way - Hemerocallis; 0); filaments often ornamented/swollen, (anthers centrifixed; anthers dehiscing by pores [Dianella and relatives]); (microsporogenesis successive), pollen usu. trichotomosulcate; stigma dry (wet); ovules 1-many/carpel, outer integument 6-7 cells across, inner integument 2-4 cells across, parietal tissue absent, nucellar cap ca 2 cells across (0), podium well developed, hypostase 0, raphides 0; antipodal cells large, persistent; fruit also a berry (nut, schizocarp); seeds ovoid, (with strophiole/aril - Johnsonia et al.); endosperm hemicellulosic, usu. helobial, embryo also short; n = 4 [Agrostocrinum], 8, 9, 11, 12, chromosomes 0.8-17.33 µm long; (cotyledon not photosynthetic - Dianella), epicotyl long or not (hypocotyl 0; collar +), primary root well developed, branched or not.

19[list]/85. Papuasia to New Zealand and the Pacific, esp. Australia (e.g. all 8 genera of Johnsoniaceae s. str., inc. Geitonoplesium, etc.), also Europe to Asia, Malesia, India, Madagascar, Africa, and two genera in South America (map: from Wurdack & Dorr 2009). [Photo - Habit, Flower, Flower].

Synonymy: Dianellaceae Salisbury, Geitonoplesiaceae Conran, Hemerocallidaceae R. Brown, Johnsoniaceae J. T. Lotsy (= Anthericaceae - Johnsonieae), Phormiaceae J. Agardh

Xanthorrhoeoideae + Asphodeloideae: (secondary thickening +); A not adnate to T; hypostase +; seeds angled.

2. Xanthorrhoeoideae M. W. Chase, Reveal & M. F. Fay   Back to Asparagales

Stem thick, woody, usu. erect; plant resiniferous; ?vessels; raphides 0; layer of sclerenchyma below epidermis in leaves; stomata paracytic; leaves spiral, unifacial, leaf base not sheathing; inflorescence spike-like, of congested cymes; pedicels not articulated; T = 3 dry + 3 subpetaloid, free; microsporogenesis successive [tetrads tetragonal], pollen extended sulcate; stigma ± punctate, ?wet; ovules several/carpel, outer integument ca 3 cells across, apex of nucellus pointed, hypostase?; inner cuticle of tegmen +; seeds flattened; endosperm quite thick-walled, development?, little hemicellulose, embryo transverse to long axis of seed; n = 11 (bimodal); hypocotyl short.

1[list]/30. Australia (map: see Bedford et al. 1986). [Photo - Habitat, - Habit, Inflorescence.]

3. Asphodeloideae Burnett

Often leaf succulents, geophytic herbs to pachycaul trees, rosette-forming; tetrahydroanthracenones [chrysophanol] in roots; (velamen +); foliar vascular bundles often inverted, parenchymatous perhaps secretory cells [aloin cells] in the inner bundle sheath adjacent to the phloem; leaves spiral or two-ranked, often fleshy, margins often toothed, sheath closed, (leaf base not sheathing); inflorescence (branched) racemose or spicate; pedicels articulated ["basal" clades] or not, ± weak monosymmetry common; T ± free (connate - Kniphofia, etc.); (anthers centrifixed); (pollen mixed with raphides); stigma dry (wet); ovules 1-many/carpel, straight [Asphodelus clade] to hemitropous [the rest], outer integument 3-4 cells across; (capsule fleshy); seed ± ovoid, aril impressed funicular [arising as annular invagination at the apex of the funicle]; endosperm thick-walled, hemicellulosic[?], (perisperm +, slight), embryo long; n = (6 - Kniphofia) 7, chromosomes 1.5-20 µm long, usu. bimodal; 3'-rps12 intron lost [Bulbine not sampled]; (coleoptile +).

Ca 15[list]/785: Aloe (400), Haworthia (54-70), Bulbine (75), Kniphofia (70),Trachyandra (50), Eremurus (45). Africa, esp. South Africa - South Africa + New Zealand (Bulbinella) - also the Mediterranean to Central Asia (map: see Reynolds 1966; Seberg 2007). [Photo - Collection, Inflorescence, Flowers.]

Synonymy: Aloaceae Batsch, Asphodelaceae Jussieu, nom. cons., Eccremidaceae Doweld [?]

• Xanthorrhoeoideae can be recognised by their habit. They have a dense tuft of long, narrow leaves terminating a stout, woody stem (and persisting as a skirt of dried leaves if there are no fires) and an long, erect, densely spike-like inflorescence with small flowers and capsular fruits.

Evolution. Divergence & Distribution. Stem group Xanthorrhoeaceae s.l. are dated to ca 93 million years before present, divergence within the crown group Xanthorrhoeaceae to ca 90 million years before present (Janssen & Bremer 2004). Excremis and Pasithea represent independent migrations of the phormioid clade to South America (Wurdack & Door 2009).

For an ecological account of Xanthorrhoea, see Lamont et al. (2004); some diversification in the genus may be associated with the aridification of the Nullarbor Plain some 14-13 million years ago separating eastern and western clades (Crisp & Cook 2007).

Vegetative Variation. Members of Asphodeloideae have more or less succulent leaves, and species of Aloe and Haworthia in particular are commonly rosette plants with fleshy leaves; these can be borne in spirals or be distinctively two-ranked. As with Aizoaceae from southern Africa, there is great variation in the micromorphology of the epidermis in Aloe and Haworthia (Cutler 1982); the two grow in similar extreme habitats. For the water-catching leaves in taxa growing in foggy deserts in Namaqualand, see Vogel and Müller-Doblies (2011).

Floral Biology & Seed Dispersal. Within Asphodeloideae, many species of Aloe are pollinated by birds, but insect pollination is also known here, as in other groups of Asphodelaceae; the directionality of evolution of pollinator relationships is unclear (Hargreaves et al. 2008). The floral monosymmetry that occurs in Haworthia and relatives is rather weak. Hemerocallidoideae often have rather elaborate stamens.

A number of Hemerocallidoideae have myrmecochorous seeds (Lengyel et al. 2010).

Chemistry, Morphology, etc. In Asphodeloideae Bulbine, Trachyandra, and Kniphofia all have knipholone, an anthraquinone derivative (van Wyck et al. 2005), but it appears not to have been reported from the Asphodelus clade. Aloin cells are reported from Dianella (Hemerocallidoideae: see Rudall 2003a); on the other hand, Kniphofia lacks aloin cells, having a well developed sclerenchymatous cap in their place (as have some other Asphodelaceae, even some Alooideae). Johnsonia (Hemerocallidoideae) has chelidonic acid (Ramstad 1953).

The apical meristem of the stem in Xanthorrhoea media is massive - 580-1283 µm across (Staff 1968, q.v. for details of stem growth). Both Hemerocallidoideae and Xanthorrhoeoideae have ovaries that can be interpreted as being secondarily superior and that have infra-locular septal nectaries (Rudall 2002, 2003a). In at least some species of Aloe the larger stamens are opposite the inner whorl of tepals. Note that ovule orientation at the basal node in the family is unclear (cf. Steyn & Smith 1998). Kniphofia has a bistomal micropyle and a nucellar endothelium (Takhtajan 1985).

There is variation in microsporogenesis in Hemerocallidoideae. Microsporogenesis in Hemerocallis was described as being successive (?alone in Hemerocallidoideae) and the endosperm as being nuclear by Di Fulvio and Cave (1965, but cf. Cave 1955). Hemerocallis also has isoflavones, monosulcate pollen and a wet stigma, but it lacks a nucellar cap and septal nectaries. In pollen morphology Hemerocallis was considered to be derived by Chase et al. (1996), indeed, it is unlikely to be sister to the rest of Hemerocallidoideae (McPherson et al. 2004). Hemerocallis also seems to have lateral bracteoles, as does Dianella; both may have "inverted" flowers (e.g. Eichler 1875; Ehrhardt 1992), although in Hemerocallis, at least, this seems to be variable. Flowers with the median outer tepal adaxial are common, but the seal of the Daylily Society shows a flower with the normal monocot orientation! The number of vascular bundles supplying the tepals in members of this subfamily varies from (1-)3-9(-25) (Clifford et al. 1998a).

Some information is taken from Cave (1955, 1975), Berg (1962) and di Fulvio and Cave (1965), all embryology, Riley and Majumdar (1979: biosystematics), Beaumont et al. (1985: leaf anatomy and chemistry), Van Wyk et al. (1995, 2005: chemotaxonomy), G. Smith and Van Wyk (1998: general), Steyn and Smith (1998: ovule morphology, 2001), McPherson et al. (2004 - loss of the 3'-rps12 intron), Reynolds (2004: esp. Aloe) and Grace et al. (2010: chemistry). See also Kosenko (1994: pollen of Phormium), Chase et al. (1996: general), Clifford and Conran (1998 - Johnsoniaceae: general), and Clifford et al. (1998a: general).

Floral tube and chelidonic acid in Xanthorrhoea? For Xanthorrhoea, some information is taken from Chanda and Ghosh (1976: pollen), Rudall (1994b: embryology), Rudall and Chase (1996: phylogeny) and Clifford (1998: general).

Phylogeny. There is strong support for Xanthorrhoeaceae s.l. in Fay et al. (2000), Wurdack and Dorr (2009), etc. See Kite et al. (2000) for the distribution of anthroquinones, McPherson et al. (2004) for taxa lacking the 3'-rps12 intron. However, relationships within the clade remain unclear. There is moderate support for [Xanthorrhoeoideae + Asphodeloideae] in the three-gene tree of Chase et al. (2000a), less in analyses including taxa with some sequences missing; see also Fay et al. (2000). However, Devey et al. (2006) find some support for a [Xanthorrhoeoideae + Hemerocallidoideae] clade (see also Pires et al. 2006; Wurdack & Dorr 2009 - slightly better than moderate support), while Chase et al. (2006, but see sampling) suggest a [Asphodeloideae + Hemerocallidoideae] clade. Rudall (2003a) suggested that there were close morphological relationships between Hemerocallidaceae (Hemerocallidoideae) and Asphodelaceae (Asphodeloideae) - and between Xanthorrhoeaceae s. str. and Iridaceae...

Within Asphodelaceae, Alooideae are very distinctive (see Klopper et al. 2010 for a summary). They are sometimes shrubby plants, and secondary growth is common. They have 1-methyl-8-hydroxyanthraquinones [e.g. chrysophanol; in roots] and anthrone-C-glycosides [in leaves]. Their sieve tube plastids also have peripheral fibres in addition to the central protein crystal. They have tetracytic stomata (e.g. Cutler 1972), although this is questioned by G. Smith and van Wyk (1992); perhaps there is variation. The leaves are notably succulent, with white or concolorous spots and tubercles. The vascular bundles in the leaf form a circle and there are globules in the outer bundle sheath (also in Kniphofia); the central cells of the leaf are gelatinous. The karyotype is bimodal. However, Bulbine is sister to Alooideae, and then come other Asphodeloideae, including Kniphofia et al. and Eremurus et al.; the Asphodelus clade is sister to all the rest of the family (good support). Thus the recognition of Alooideae makes Asphodeloideae paraphyletic (see Devey et al. 2006 for a phylogeny, inc. details of that of Bulbine, also references below). Some species of Bulbine have a bimodal karyotype on n = 7 (4 long, 3 short: Spies & Hardy 1983), rather like the karyotype of Aloeae (4L + 3S: probably evolved independently, see Devey et al. 2006; Pires et al. 2006), and also the same medicinal properties... For relationships around Aloe, see Treutlein et al. (2003a, b), and for those around Haworthia, see Ramdhani et al. (2011: species limits difficult, hybridization).

There are two well supported clades within Hemerocallidoideae, the phormioid and [hemerocallid + johnsonioid] clades (Wurdack & Dorr 2009). Pasithea is siter to all other phormioids, and it has completely bifacial leaves, i.e. the plesiomorphic condition (Wurdack & Dorr 2009). The loss of the 3'-rps12 intron characterises a major clade [Johnsonieae + Hemerocallis + Simethis], i.e. the latter clade above, see McPherson et al. (2004) and Chase et al. (2000b). The New World Eccremis, previously of uncertain relationships, was found to be sister to Dianella (Wurdack & Dorr 2009).

Excremis coarctata is odd; it was initially placed here only with hesitation (see Clifford et al. 1998a; Devey et al. 2006): pedicel articulated; A connate basally, 3 [which whorl?] adnate to T; also a septicidal endocarp: 1 sp., Andean (for anatomy, see Ely & Luque Arias 2006, the base of the leaf is isobifacial). It has the habit of Phormium, and it was sometimes included in Phormiaceae (= Hemerocallidaceae s. str./Hemerocallidoideae). The only other South American member of Asphodeloideae is Pasithea. Wurdack and Dorr (2009) found that both were members of the phormioid clade.

Classification. A.P.G. II (2003) suggested as an option including Asphodelaceae, Xanthorrhoeaceae and Hemerocallidaceae in Xanthorrhoeaceae s.l., and this circumscription was adopted by A.P.G. III (2009). The subfamilial classification above follows that in Chase et al. (2009b).

Species estimates in Dianella (Hemerocallidoideae) range from 25-350+ (Carr 2007). Generic limits around Aloe (Asphodeloideae) are decidedly unsatisfactory (e.g. Treutlein et al. 2003a, b; Klopper et al. 2010), while species limits are also problematic there, and in Kniphofia, Haworthia, as well as in Asphodeloideae (Bayer 2009 for some comments and references). G. Smith and Steyn (2004) discuss the taxonomy of Alooideae (= Aloeae), and Carter et al. (2011) offer a well-illusrated account of Aloe (500+ species?).

Thanks. I thank Syd Ramdhani and Matt Ogburn for useful discussions.

Previous Relationships. Three genera that used to be placed in Asphodelaceae s. str. are now in Hemerocallidoideae (Simethis), Asparagaceae-Asparagoideae (Hemiphylacus), and Asparagaceae-Agavoideae (Paradisea, Anthericaceae s. str.) respectively - the evidence is largely molecular (Chase et al. 2000b).

Amaryllidaceae + Asparagaceae: microsporogenesis successive [possible place]; endosperm development?

Evolution. Divergence & Distribution. This clade separates from Xanthorrhoeaceae s.l. ca 93 million years before present, divergence within it begins at ca 91 million years before present (Janssen & Bremer 2004), corresponding figures given by Wikström et al. (2001) are 61-54 and 58-51 million years before present respectively.

Chemistry, Morphology, etc. Where do steroidal saponins occur in this clade? Microsporogenesis is uniform in this group. In other Asparagales that also have successive microsporogenesis, details of wall formation (centrifugal cell plates) is similar to those members of this clade that have been studied, however, where microsporogensis is simultaneous, plate formation may also be centripetal (Nadot et al. 2006). For chromosome size in Liliaceae s.l. and supposed relatives, see Vijayavalli and Mathew (1990).

Phylogeny. This is a strongly supported clade (e.g. Chase et al. 1995a; Fay et al. 2000; Chase et al. 2000b; Graham et al. 2005). However, inclusion of Aphyllanthaceae/Asparagaceae-Aphyllanthoideae in analyses has tended to decrease support for clades within it (Graham et al. 2006). Note that Kim et al. (2011: seven genes, three compartments) found that Amaryllidaceae grouped with Asparagoideae, Lomandroideae and Nolinoideae; other members of this clade formed a separate group.

AMARYLLIDACEAE J. Saint-Hilaire, nom. cons.   Back to Asparagales

Lectins binding mannose; leaves two-ranked; inflorescence scapose, umbellate, construction cymose, with scarious spathe, inflorescence bracts 2 (or more - external); pedicels not articulated; (T free); (A connate basally), (tapetal cells uninucleate); style long, stigma dry; parietal tissue absent; endosperm nuclear or helobial; hypocotyl 0.

73/1605. Worldwide - three subfamilies below.

Evolution. Divergence & Distribution. Stem group Amaryllidaceae are dated to ca 91 million years before present, divergence within crown group Amaryllidaceae begins ca 87 million years before present (Janssen & Bremer 2004).

Bacterial/Fungal Associates. Fungi on Allium and other Allioideae are rather different from those on Amaryllidoideae (e.g. Savile 1962).

Chemistry, Morphology, etc. Distinctive, mannose-binding lectins (the specificity is absolute) are found in Allioideae and Amaryllidoideae (van Dammme et al. 1991); I do not know if they have been recorded from Agapanthus. Very large genomes with a C value of some 350 picograms or more are found in some Amaryllidaceae-Allioideae and -Amaryllidoideae - also in Asparagaceae-Scilloideae (Leitch et al. 2005). For tapetal cells, see Wunderlich (1954), for inflorescence structure, see Weberling (1989).

Phylogeny. This is a very strongly supported clade (e.g. Fay et al. 2000, but cf. McPherson et al. 2004; Thomas et al. 2005), and it has some characters! Meerow et al. (1999), Fay et al. (2000: strong support), Givnish et al. (2006) and Pires et al. (2006) suggest a set of relationships [Agapanthaceae [Alliaceae + Amaryllidaceae]], although Meerow et al. (2000a) found Agapanthaceae to be sister to Amaryllidaceae, albeit with weak support.

Classification. Combining the three families Agapanthaceae, Alliaceae and Amaryllidaceae into Alliaceae s.l. was an option in A.P.G. II (2003), an option that was exercised in A.P.G. III (2009), although the name of the clade is there Amaryllidaceae. The infrafamial classification follows that in Chase et al. (2009b).

1. Agapanthoideae Endlicher

Plant rhizomatous; leaf vernation flat; inflorescence bracts connate along one side; flowers large, monosymmetric, T ± connate basally; anther wall development dicotyledonous; ovules apotropous; seeds flat, winged; endosperm with starch/hemicellulose, embryo short; n = (14) 15 (16), chromosomes 4-9 µm long; seedling as in Allioideae?

1/9. South Africa (map: from Leighton 1965). [Photo - Habit, Flower.]

• Agapanthoideae are rather robust, rhizomatous herbs that can be recognised by their rather fleshy and two-ranked leaves and their scapose umbellate inflorescence of generally large flowers with superior ovaries.

Chemistry, Morphology, etc. Information is taken from Kubitzki (1998b: general); D. Zhang et al. (2010) describe sporogenesis and gametogenesis, Zhang et al. (2011) embryogeny.

Synonymy: Agapanthaceae F. Voigt

Allioideae + Amaryllidoideae: geophytes, bulbs sympodial, tunicate, with contractile roots; (embryo sac bisporic, eight nucleate).

2. Allioideae Herbert

Flavonoids, cysteine-derived sulphur compounds +; also styloids +; laticifers +; leaves (spiral), sheath closed, long, shortly ligulate [Allium, at least]; floral bracts 0; T ± connate; A connate or adnate to free; (stigma wet); style solid; ovules 2-many carpel, in two ranks, campylotropous (anatropous), (micropyle bistomal), nucellar cap + (?0), obturator +; seeds angular, exotestal, other layers of testa collapsed or not; (endosperm pitted); chromosomes 2-20 µm long; (cotyledon not photosynthetic).

13[list]/795. Mainly South America, but Allium esp. N. Temperate Eurasia - three groups below. [Photo - Collection] [Photo - Inflorescence, Flower, Flower.]

2A. Allieae Dumortier

Bulbs lacking starch; vessel elements in roots often with simple perforation plates; (leaves ± unifacial); T basally connate, (one-nerved), corona 0; A both basally connate and adnate to C, filaments often winged, tapetal cells uninuclear; (G semi-inferior), style ± gynobasic, (paired projections from the ovary); ovules 2-14/carpel, epitropous; (seed with caruncle); endosperm cellular, embryo long, curved; n = (7) 8 (9), chromosomes 9.0-19.3 µm long, telomeres distinctive [?how common in family].

1/260-780: all Allium! North temperate, often seasonally dry, especially the Mediterranean to Central Asia, west North America, scattered in Africa (map: from Hultén 1962; de Wilde-Duyfjes 1976; Hanelt 1990; Hanelt et al. 1992; Fl. N. Am. 26: 2002, n.b. not native in Iceland).

Synonymy: Alliaceae Borkhausen, nom. cons., Cepaceae Salisbury, Milulaceae Traub

Tulbaghieae + Gilliesieae: bulbs with starch; endosperm helobial.

2B. Tulbaghieae Meisner

Plant often rhizomatous; leaf sheath short; flowers bracteate; T rather strongly connate, corona massive, lobes connate or not; A sessile, adnate to corolla tube and/or corona; ovules 2-several/carpel; seeds ± flattened; embryo?; n = 6, chromosomes 11.5-14.7 µm long.

1/22. Southern Africa (map: from Vosa 1975).

Synonymy: Tulbaghiaceae Salisbury

2C. Gilliesieae Baker

Corona +/0, (A 2-3; variously connate and adnate; extrorse; staminodes +); ovules 2-many/carpel, (inner integument 5-7 cells across - Dichelostemma); embryo short; n = ³4.

10/80: Nothoscordum (22). South U.S.A., Mexico to South America (map: from Fl. N. Am. 26. 2002).

Synonymy: Gilliesiaceae Lindley

• Allioideae can be recognised by their smell, their often rather fleshy and soft leaves, and their scapose umbellate inflorescence with medium-sized flowers that have superior ovaries.

Evolution. Divergence & Distribution. Nguyen et al. (2008) found that Old and New Word species of Allium are mostly in two separate clades, although basal to the clade containing all North American members (they belong to subgenus Amerallium) are Eurasian taxa. Diversity within North America Allium is centered in the west, especially in California, and a number of species there are serpentine endemics (Nguyen et al. 2008).

Floral Biology & Seed Dispersal. In Gilliesieae, Gilliesia has very strongly monosymmetric flowers with only two stamens; the flowers may mimic insects (Rudall et al. 2002).

Chemistry, Morphology, etc. The apparently bifacial leaves of at least some species of Allium have inverted vascular bundles along the adaxial surface and vascular bundles with normal orientation along the abaxial surface (Mathew 1996); I do not know how widely this feature is spread in the family.

Some information is taken from Berg (1996) and Berg and Maze (1966), both embryology, and Rahn (1998: general). For Allium, see Rabinowitch and Currah (2002: more horti-/agricultural), Fritsch and Friesen (2002 [and many other papers in same book]: general), Fritsch and Keusgen (2006: cysteine sulphoxide distribution), and Choi et al. (2011: floral development, esp. epidermis).

In Gilliesieae, Schickendantziella has only three tepals; they are caudate. Nothoscordum has solid styles.

Phylogeny. Fay and Chase (1996) discuss relationships within the subfamily; the topology is [Allieae [Tulbaghieae + Gilliesieae]], although the support for the clades is rather weak. Nguyen et al. (2008) provide a phylogeny for Allium (see also Friesen et al. 2006; Hirschegger et al. 2010 - section Allium); the relationships of members of the small subgenera Nectaroscordum and Microscordum are unclear (Nguyen et al. 2008). In the large subgenus Melanocrommyum of Allium there seems to be extended incomplete lineage sorting, and morphological sections are not supported by molecular data (Gurushidze et al. 2008, esp. 2010).

Classification. Friesen et al. (2006) provide a subgeneric and sectional classification of Allium; Gregory et al. (1998) list names included in it. See Vosa (1975) for a revision of Tulbaghia and details of its cytology.

3. Amaryllidoideae Burnett   Back to Asparagales

Norbelladine alkaloids, non-protein amino acids, chelidonic acid +, saponins 0; exodermis with long and short cells, 2-4-layered velamen; sclerechymatous ring in scape, bundles in rings; petiole bundles in arc; (lacunae formed by breakdown of parenchyma); leaves (spiral), flat or revolute to involute, (vascular bundles inverted; base sheathing); bracts equitant; flowers large, (monosymmetric, with median member of outer tepalline whorl adaxial; T ± free, corona +/0 [morphology various]; anther wall development dicotyledonous; ovary inferior, stigma capitate to deeply trifid, (wet); (ovule with outer integument 3< cells across); endosperm starchy or with hemicellulose (thin-walled), embryo poorly differentiated, small; n = (5-)11(12<), chromosomes (1.5-)3-28 µm long; cotyledon bifacial, (not photosynthetic), primary root well developed, contractile.

59[list]/800+ - fourteen groups below. Tropical (temperate), esp. South America and Africa, also Mediterranean (map: from Allan Meerow and O. Seberg, pers. comm.; Snijman 1984; Fl. N. Am. 26: 2002). [Photo - Flower, Fruit.]

3A. Amaryllideae Dumortier

Stomata paracytic, subsidiary cells with oblique divisions; extensible [helically-thickened] fibres in leaf; leaves follow the flowers, (perennial - many Crininae); corona of webbing joining filaments basally, or small appendages developed from filaments, or 0 [Crineae]; pollen bisulcate, exine gemmate, with scattered spinules, intectate-columellate; (style laterally displaced); ovules unitegmic; embryo sac Allium type; seeds water-rich, non-dormant, phytomelan 0, testa to 25 cells thick, chlorophyllous, with stomata, or ± collapsed, or 0; endosperm usu. with a corky layer, chlorophyllous, starchy, embryo chlorophyllous; (n = 10, 12, 15), chromosomes 5.3-20.5 µm long.

11/146: Crinum (65), Strumaria (23). SubSaharan, especially South Africa, Crinum Pantropical.

Synonymy: Crinaceae Vest, Strumariaceae Salisbury

Cyrtantheae, etc.: bundle sheath cells parenchymatous.

3B. Cyrtantheae Traub

Scape lacking sclerenchymatous ring, subepidermal collecnchyma +; 1-layered rhizodermis +, velamen 0; seeds flat, winged, horizontally stacked, phytomelan +; n = (7) 8 (11).

1/50 (Cyrtanthus). Africa, especially the south.

Synonymy: Cyrtanthaceae Salisbury

[Calostemmateae + Haemantheae]: fruit indehiscent.

3C. Calostemmateae D. & U. Müller-Doblies

Ovules 2-3/carpel; embryo germinates precociously producing a bulbil; fruit dry; phytomelan 0; n = 10, chromosomes 3.3-8 µm long.

2/4. Australia, Malesia.

3D. Haemantheae Hutchinson

(Plant rhizomatous); (alkaloids 0 - Gethyllis); 1-layered rhizodermis +, velamen 0; scape lacking sclerenchymatous ring, subepidermal collenchyma +; inflorescence bracts connate, (flowers single - Gethyllis, etc.); (A 12); fruit baccate; seeds angled, etc.; phytomelan 0 (+); n = 6, 8, 9, 11, 12; chromosomes 5.2-24 µm long.

6/80: Gethyllis (32), Haemanthus (22). Tropical Africa, mostly in the South.

Synonymy: Gethyllidaceae Rafinesque, Haemanthaceae Salisbury

[Lycoridae [Galantheae, Pancratieae, Narcisseae]] / Eurasian Clade: seeds subglobose, turgid.

3E. Lycoridae D. & U. Müller-Doblies

(Seeds irregularly discoid - Ungernia); n = 11 (etc.).

2/26: Lycoris (20). Temperate to subtropical East Asia to Iran.

[Galantheae, Pancratieae, Narcisseae]: ?

3F. Galantheae Parlatore

(Inflorescence bractes connate along one side); (anthers dehiscing by pores); elaiosome + (0); n = 7-9, 11, 12.

8/31: Galanthus (17). Europe to N. Africa, the Crimea and the Caucasus.

Synonymy: Galanthaceae G. Meyer, Leucojaceae Borkhausen

3G. Pancratieae Dumortier

Staminal tube toothed; n = 11, chromosomes 8.7-22 µm long.

1/20. Mediterranean, southern Asia, to sub-Saharan Africa.

Synonymy: Pancratiaceae Horaninow

3H. Narcisseae Lamarck & de Candolle

Inflorescence bracts basally connate; (corona + - Narcissus); elaiosome + (0); n = (7) 11 (13), etc.

2/58: Narcissus (50). Europe to W. Asia and N. Africa.

Synonymy: Narcissaceae Jussieu

[Hippeastreae [Eustephieae [Hymenocallideae, Stenomesseae, Eucharideae]]] / Andean + extra-Andean/American clade: 1-layered rhizodermis +, velamen 0; scape lacking sclerenchymatous ring, subepidermal collenchyma +; bracts obvolute; (seeds flat, horizontally stacked), phytomelan common.

3I. Hippeastreae Sweet

Inflorescence bracts often connate basally (along one side); flowers (very strongly) monosymmetric; (corona +); A declinate, of varying lengths; seeds flattened, winged or D-shaped; n = 8-13, 17, etc., chromosomes 3-16.7 µm long.

11/218: Hippeastrum (55, the "Amaryllis" of many a windowsill), Zephyranthes (50), Habranthus (50). S.E./S.W. U.S.A., the Caribbean, and Central and South America.

Synonymy: Brunsvigiaceae Horaninow, Oporanthaceae Salisbury, Zephyranthaceae Salisbury

[Eustephieae [Hymenocallideae, Stenomesseae, Eucharideae]] / Andean tetraploid clade: no palisade leaf mesophyll; flowers polysymmetric; x = 23 [tetraploid].

3J. Eustephieae Hutchinson

A of two lengths; seeds flattened, winged; (n = 21, etc.).

3/15: C. Andes (Peru, Bolivia, Argentina).

[Hymenocallideae, Stenomesseae, Eucharideae]: ?

3K. Hymenocallideae Small

Pollen grains auriculate [the two ends narrowed, with different sculpture]; testa thick, spongy, chlorophyllous, vascularized, phytomelan 0 (+ - Leptochiton); embryo starchy; (n = 19, 20, 22), chromosomes 4-11.8 µm long.

3/65: Hymenocallis (50). S.E. U.S.A., the Antilles, Central America to Bolivia.

3L. Stenomesseae Traub

(Velamen + - Pamianthe); leaves petiolate, lorate; staminal cup + (0); seeds flattened, obliquely winged.

8/62: Stenomesson (35). Andean South America S. to Bolivia, Costa Rica (1 sp.).

3M. Eucharidae Hutchinson

Leaves petiolate; (flowers monosymmetric); seeds globose, turgid, coat lustrous; chromosomes 2.3-10.7 µm long.

4/28: Eucharis (17). Central America, the Andes S. to Bolivia.

• Amaryllidoideae are usually bulbous herbs that can be recognised by their rather fleshy and two-ranked leaves and their scapose, umbellate inflorescence of generally large flowers with six stamens and an inferior ovary.

Evolution. Ecology & Physiology. Amaryllidoideae form an important component of the distinctive Cape geophyte flora (Procheŝ et al. 2006) having about 100 species endemic there. For water-catching leaves with very distinctive morphologies that are found ecpecially in taxa from Namaqualand, see Vogel and Müller-Doblies (2011).

Floral Biolgy & Seed Dispersal. Monosymmetry is ancestral in the subfamily (Meerow & Snijman 1998; Meerow 2010), but it seems to be very labile, perhaps being under simple genetic control (Meerow et al. 1999); reversals and parallelisms in this feature are common. Some kind of corona is sommon; it can be distinct from the anthers, or form a tube, sometimes toothed (Pancratium), on which the stamens are born, or it may consist of short wings from the filamens. The flowers are protandrous. Meerow (2010) discusses diversification in American Amaryllidaceae in terms of interpaly of canalization and genome doubling, emphasizing the floral and vegetative diversity encompassed by the Andean tetraploid-derived clade.

Almost three hundred species in the family have myrmecochorous seeds (Lengyel et al. 2010). Wind dispersal of the inflorescences is common in Amaryllideae, the rigid, radiating pedicels allowing the infructescences to bowl along. The testa is commonly massive, green, and with anomocytic stomata in Amaryllidinae; it is photosynthetic, while in Crinum, of the same tribe, it is the endosperm that is green and photosynthetic. Seeds of some species of Crinum lack a testa and may have a corky outer endosperm; such seeds can float and remain viable in sea water for up to two years, while seeds of other species lack the corky layer, sink fast and can germinate without very much in the way of water at all (Snijman & Linder 1996; Bjorå et al. 2006). In Calostemmateae the bulbil, a precociously-germinated embryo, is the dispersal unit. Gethyllis (Haemantheae: to include Apodolirion) have single flowers with a subterranean ovary; the many-seeded fruit is indehiscent, and may be sweetly scented when ripe.

Chemistry, Morphology, etc. Norbelladine alkaloids, unique to Amaryllidoideae, are tyrosine derivatives; they are responsible for the poisonous properties of a number of the species. Over 200 different structures are known, or which 79 or more are known from Narcissus alone (Bastida & Viladomat 2002 and other references in the same volume, also Martin 1987; Rønsted et al. 2008b: the phylogeny of Narcissus in the context of the distribution iof acetylcholinesterase-inhibiting alkaloids; Larsen et al. 2010: Galantheae, also a phylogeny; Bay-Smidt et al. 2011: acetylcholinesterase inhibition, etc., in Hameantheae; Jensen et al. 2011: alkaloids with similar inhibition in Calostemmateae).

Because of the leaf fibres in Amaryllideae, the coverings of the bulbs produce highly-extensible cotton-like fibres when torn. There are often crystals of calcium oxalate in the epidermis. Petiolate leaves have evolved at least six times in the family.

The flowers of Galanthus are shown with the median member of the outer whorl in the adaxial position (Spichiger et al. 2004), see also the similar position in Hippeastrum and several other monosymmetric Amaryllidoideae. Some species of Phaedranassa have slit-monosymmetric flowers, with all the stamens, etc., leaving the flower via an abaxial slit in the perianth tube; I do not know details of the symmetry of such flowers. Flowers of some species of Crinum are monosymmetric. In Galanthus in particular the inner whorl of tepals is very different from the outer whorl, although both are petaloid.

In Strumaria and Carpolyza the bases of the filaments are adnate to the style, while in Strumaria and Tedingia the base of the style may be much inflated, even bulbous. Note that the "coronal" structures of e.g. Hymenocallis (evascularized outgrowths of the filaments) and those of Narcissus (vascularized, not associated with the stamens) are quite different (e.g. Arber 1937). Haemanthus has tepals with a single trace. Flowers of Gethyllis have up to 18 stamens, and chromosomes in a single nucleus may be 3-16.1 µm long. Crinum has cellular endosperm. Raymúndez et al. (2008) described megasporogenesis and megagametogenesis in Hymenocallis caribaea; the ovules is crassinucellate ("pseudocrassincellate"), the micropyle ia zig-zag, and the vascularized outer integument is massive. x = 11 may be the basal chromosome number for the family (Meerow et al. 2006). It is unclear if some ovules are ategmic. A very long-tubular dropper cotyledon sheath may be produced during germination; in Boophone and Cybistes germination may occur while the seeds are still enclosed by the fruit.

For anatomy, see Arroyo and Cutler (1984), for pollen, see DÖnmez and Isik (2008), and for general information, see Meerow and Snijman (1998).

Phylogeny. For the phylogeny of Allioideae, see Fay et al. (2006b); part of Ipheion is embedded in Nothoscordum. Phylogenetic relationships within Amaryllidoideae are [Amaryllideae [Cyrtantheae [Calostemmateae, Haemantheae, Gethyllideae [Eurasian Clade [Andean Clade, Extra-Andean Clade]]]]] see Meerow et al. (1999, 2000a, 2000b). Note, however, that relationships between major clades of American and some southern African members are not well understood. Furthermore, Meerow et al. (2006) found that the inclusion of Hannonia, Lapiedra and Vagaria destabilised relationships in the European clade; Lledó et al. (2004) included the last two in Galantheae. Meerow and Clayton (2004) discuss relationships among African taxa.

For a phylogeny of Cyrtanthus and discussion on its evolution, see Snijman and Meerow (2010); molecules and cytology, but less morphology, tend to agree. Meerow and Snijman (2001, see also 2006) discuss relationships within Amaryllideae; Amaryllis and Boophone are successively sister to the rest of the tribe. Note that the former genus differs from other Amaryllidineae in not having a green testa, etc. Meerow et al. (2003) outline the phylogeny of Crinum, the only pantropical member of Amaryllidaceae. For a phylogeny of Crinum, see Kwembeya et al. (2007).

For relationships in Haemantheae, see Conrad et al. (2006) and Bay-Smidt et al. (2011). Meerow et al. (2006) provide a phylogeny for the Eurasian Clade, which includes daffodills, snowdrops, etc. The main dichotomy separates the Central and East Asian Lycorideae from the rest, which centre on the Mediterranean region. ITS and ndhF phylogenies are not congruent (Meerow & Snijman 2006). For a phylogeny of Galantheae, see Lledó et al. (2004) and for that of Narcissus and acetylcholinesterase-inhibiting alkaloids, see Rønsted et al. (2008b).

Within Hippeastreae, Worsleya and Griffinia (Griffinieae: n = 10, 21; velamen + [Worsleya]; flowers blue; seeds whitish, globose, turgid [Griffinia]) are morphologically isolated and have an isolated position in Meerow et al. (2000a: as the "Hippeastroid" clade).

Classification. For the infrafamilial classification of Amaryllidaceae, I follow Chase et al. (2009: c.f. Fay and Chase 1996 for Allioideae). For a classification of Amaryllideae, see Meerow and Snijman (2001, 2006), and for generic limits in Galantheae, see Lledó et al. (2004).

ASPARAGACEAE Jussieu, nom. cons.   Back to Asparagales

Inflorescence racemose.

153/2480. World-wide, but not Arctic - seven groups below.

Evolution. Divergence & Distribution. Stem group Asparagaceae s.l. are dated to ca 91 million years before present, divergence within crown group Asparagaceae s.l. begins ca 89 million years before present (Janssen & Bremer 2004). Eguiarte (1995), however, suggested that Agavaceae-Nolinaceae - the two are members of the two main clades here - diverged only some ca 47 million years ago,

Phylogeny. These seven subfamilies form a rather well supported clade in Fay et al. (2000: Hesperocallis not included), but there are no obvious characters for it. However, it is possible that "endosperm helobial, thick-walled, pitted, hemicellulosic" should be placed at this level. For details of relationships, see also Jang and Pfosser (2002) and Bogler et al. (2006). Fay et al. (2000), Pires et al. (2001), and Pires and Sytsma (2002) discuss uncertainties as to the immediate sister taxon to Themidaceae. Aphyllanthes has a very long branch in the three-gene analysis of Fay et al. (2000), and its phylogenetic position is unclear, indeed, its removal from some analyses rather dramatically changes support values (Chase et al. 2006). A position close to Hyacinthaceae was also found by McPherson and Graham (2001), but Pires et al. (2006) place it sister to Laxmanniaceae, but with only weak support. Themidaceae + Hyacinthaceae appear a moderately well supported pair in Fay and Chase (1996) and Meerow et al. (2000), but only weak support in the two-gene analysis of Jang and Pfosser (2002: Aphyllanthus not included) and in Chase et al. (2006) and Pires et al. (2006).

Chemistry, Morphology, etc. For anatomy, etc., of members of old "Agavaceae", see Wunderlich (1950).

Classification. In addition to the absence of much in the way of synapomorphies for the clade, most of the subfamilies are difficult to recognise, for the most part having rather undistinguished "lily"-type flowers. Within some of them, e.g. Asparagoideae and especially Nolinoideae and Agavoideae, there is considerable variation, several segregate families having been recognised in the past. Also, a broadly circumscribed Agaveae included members of what are now different clades in Asparagaceae s.l. (cf. Wunderlich 1950). Hence the use of Asparagaceae s.l. to refer to the entire clade is justified (cf. A.P.G. II 2003, A.P.G. III 2009). The subfamilial classification follows that in Chase et al. (2009b).

[Aphyllanthoideae [Brodiaeoideae + Scilloideae] Agavoideae]: ?

1. Aphyllanthoideae Lindley   Back to Asparagales

Flavonols +; vessel elements in roots often with simple perforation plates; stem secondary growth +; stems alone photosynthetic, with parallel wax scales; leaves two-ranked, supervolute-subinvolute, as non-photosynthetic scales, ligulate, base?; inflorescence scapose, flowers multibracteolate, sessile; T marcescent, basically free; A adnate to base of T; pollen spiraperturate; ovary sulcate down middles of loculus; infra-locular septal nectaries +, stigma trifid, dry; ovule 1/carpel, micropyle?; seeds slightly flattened, exotestal cells large, isodiametric; endosperm ?, 0; n = 16; cotyledon photosynetic, terete, first leaf terete.

1[list]/1: Aphyllanthes monspeliensis. W. Mediterranean. [Photo - Flower © E. Bourneuf]

• Aphyllanthaceae may be readily recognised; the above-ground plant consists of tufts of scapose infloresences, the scapes being the main photosynthetic organs since the scarious leaves at their bases are non-photosynthetic; the inflorescence is few-flowered, the spreading, usually blue tepals being moderate in size (the whole plant looks rather like Sisyrinchium!).

The stomata are in bands down the scape. The tepals have but a single bundle. Is there chelidonic acid?

General information is taken from Conran (1998); he mentions endosperm development as being helobial, but there is no mention of this in Schnarf and Wunderlich (1939), which appears to be the only source of information for ovule features.

Synonymy: Aphyllanthaceae Burnett

[Brodiaeoideae + Scilloideae]: steroidal saponins +; leaves spiral; inflorescence scapose, pedicels bracteate; raphides in carpel wall; ovules anatropous; endosperm helobial or nuclear; cotyledon not photosynthetic.

For some characters of this pair, see Fay and Chase (1996); laticifer-like structures may occur in both.

2. Brodiaeoideae Traub   Back to Asparagales

Fibrous monopodial corm storing starch; laticifers +; mucilage cells?; leaves (unifacial - Brodiaea), sheath closed; inflorescence umbellate, cymose, with several scarious inflorescence and internal bracts, pedicels often articulated; (T free; corona +); A (3), connate and/or adnate to T, (filaments flattened); (ovary stipitate, adnate to T by flanges opposite the outer tepals), stigma capitate to trifid, dry (wet - Bloomeria); outer integument 3-4 cells across, (inner integument 3+ layers across), parietal tissue 3-4 cells across, (nucellar cap +); seeds angular, cells of tegmen much enlarged (not - Triteleia); (endosperm helobial - Muilla, Triteleia), "embryo short"; n = 5-12+; hypocotyl?, primary root persistent.

12[list]/62. S.W. North America, to British Columbia and Guatemala (map: see Moore 1953; Fl. N. Am. 26: 2002). Flower, Flower, Fruit.]

• Asparagaceae-Brodiaeoideae are like Amaryllidaceae-Allioideae in their scapose, umbellate inflorescence, rather small flowers, more or less connate tepals sometimes with a corona, and a superior ovary, but the plants have a fibrous corm, not a bulb, and lack the distinctive smell common in the latter family, and there are usually 4 or more inflorescence bracts that are not as all-enveloping as the ca 3 bracts of Allioideae.

Chemistry, Morphology, etc. Little is known of the chemistry of the subfamily. When the tepalline tube is adnate to the stipitate gynoecium, three narrow, ?nectar-containing tubes are formed. Embryologically this group is quite variable. The inner integument is massive or not, ditto base of the nucellus, endosperm development vaies, etc. (Berg 2003 for a summary).

Information is taken from Moore 1953 (morphology), Berg (1978: embryology), Rahn (1998: general).

Phylogeny. There are two major clades in the Brodiaeoideae, albeit they have only only moderate support. One has a long tepalline tube and the other has appendages on the bases of the filaments that form a nectar cup; both characters arise in parallel in the opposing clade (Pires & Sytsma 2002). See also Pires et al. (2001) for phylogeny and morphological evolution; [Muilla, Triteleia] and [Dipterostemon, Dichelostemma, Brodiaea] are the two clades.

Previous Relationships. Themidaceae/Brodiaeoideae have often been included in Amaryllidaceae-Allioideae because of their superficially similar umbellate inflorescence and rather "typical"-appearing and undistinguished monocot flowers (e.g. Takhtajan 1997).

Synonymy: Themidaceae Salisbury

3. Scilloideae Burnett  Back to Asparagales

Plant bulbous geophytes, roots often contractile, bulb leaves sheath closed or not; polyhydroxyalkaloids, flavones +, flavone C-glycosides +; little sclerenchyma in the leaf (well-developed); mucilage cells +; (leaf waxes with parallel platelets); inflorescence (branched), (spike), pedicels not articulated, bracteole 0; (corona +); (style solid - Nothoscordum), stigma capitate to punctate and papillate; ovules 1-many/carpel, o.i. 3, parietal tissue usu. 2-4 cells across, (nucellar epidermis radially elongated), nucellar cap +/0, raphides +, obturator +; (postament +); testa multi-layered; chromosomes 1.2-18 µm long; (hypocotyl 0; collar rhizoids +).

41-70[list]/770-1000 - six groupings below. Predominantly Old World, Mediterranean climates, esp. S. Africa and the Mediterranean, to Central Asia and Burma; some in South America.

3A. Oziroëeae M. W. Chase, Reveal & M. F. Fay

A basally connate and adnate to C; seeds rounded; embryo long; n = 15, 17; cotyledon?.

1/5. Western South America (map: see opposite, green colour, from Guaglianone & Arroyo-Leuenberger 2002).

[Ornithogaleae + Urgineeae + Hyacintheae]: rhexigenetic lacunae +; also styloids +; (pollen mixed with raphides).

3B. Ornithogaleae Rouy

Cardenolides +; (A 3; filaments flat, with appendages); seeds flattened/angled; protein crystals in nucleus; n = 2-10+; cotyledon photosynthetic or not.

4/312: Ornithogalum (160), Albuca (110-140). Europe, W. Asia, Africa.

Synonymy: Ornithogalaceae Salisbury

3C. Urgineeae Rouy

Bufadienolides +; bracts spurred [as small leaves in Bowiea]; (stylar canals 3 - Boweia); seeds flattened/winged, testa brittle, not tightly adherent to endosperm; n = 6, 7, 10+.

2(-3?)/105: Drimia (100, inc. Urginea). Mainly Africa, Madagascar, the Mediterranean to India (map: from Pfosser & Speta 2001). [Photos - Boweia Collection.]

Synonymy: Hyacinthaceae Borkhausen

3D. Hyacintheae Dumortier

Homoisoflavanones +; (leaves with pustules or coloured spots); embryo sac type variable; seeds often rounded.

a. Pseudoprospero

Prophylls +; 2 ovules/carpel; 1 seed/loculus; n = 9; cotyledon not photosynthetic.

1/1: Pseudoprospero firmifolium. E. South Africa.

b. Massoniinae Bentham & Hooker f.

(Bracteoles +); (flowers monosymmetric); ovary and style sulcate, style with 3 canals; ovules 2-many/carpel; (elaiosomes +); n = 5-10+; cotyledon not photosynthetic (photosynthetic).

Ca 10/235: Lachenalia (110), Ledebouria (70). Africa S. of the Sahara, Ledebouria to India (map: from Venter 2008).

Some species of Daubenya (Massoniinae) have a filament tube.

Synonymy: Eucomidaceae Salisbury, Lachenaliaceae Salisbury

c. Hyacinthinae Parlatore

(Bracts 0), prophylls quite common; style with single canal, canal papillate; 2-8(-many) ovules/carpel, outer integument 4-5 cells across, parietal tissue 2-3 cells across; antipodal cells large; (elaiosomes +); n = 4-8+; cotyledon photosynthetic or not.

21/265: Muscari (50), Bellevalia (50), Scilla (30), Prospero (25). Europe to the Mid (Far) East, North Africa (map: above, area in red, from Meusel et al. 1965, incomplete). [Photo: Scilla Collection.]

Synonymy: Hyacinthaceae Borkhausen, Scillaceae Vest

• Scilloideae are bulbous monocots with rather fleshy, mucilaginous leaves that are all basal. The scapose, racemose inflorescence bears for the most part rather undistinguished monocot flowers with more or less connate tepals; the fruit is a capsule.

Evolution. Divergence & Distribution. Oziroë diverged from the rest of the clade in the Oligocene ca 28 million years ago, while divergence in the rest began only ca 18.8 million years ago early in the Miocene. The subfamily may have originated in sub-Saharan Africa and dispersed north and also east, details depending on the analytic method used (Ali et al. 2012).

There are about 300 species of Scilloideae in the Cape flora alone (Procheŝ et al. 2006). Several Scilloideae growing in the foggy deserts of Namaqualand have water-catching leaves with very distinctive morphologies (Vogel & Müller-Doblies 2011).

Floral Biology & Seed Dispersal. Lachenalia has monosymmetric flowers in which the median member of the outer whorl is in the adaxial position. The same is true of the remarkable monosymmetric flowers of Massonia (Daubneya) aurea that are on the outside of the inflorescence. These flowers have the three abaxial tepals greatly enlarged, while the inner flowers are polysymmetric and the tepals form a simple, lobed tube. Pollination in Albuca is noteworthy in that the pollen is deposited by the bee on the tips of the inner tepals and pollination does not take place until the flower withers and the tepals press against the stigma (Johnson et al. 2009b).

Species with myrmecochorous seeds are scattered throughout the subfamily (Lengyel et al. 2010).

Chemistry, Morphology, etc. Some species of Scilloideae have terete, unifacial leaves, and even the bulb scales of some species of Rhadamanthus (= Drimia) are terete... Asparagus (Asparagoideae) also has stem/branch leaves that have a backwardly-directed process like those on the leaves and/or bracts of Urgineeae (Scilloideae). Vegetative variation - in both leaf and bulb - is also considerable in Ledebouria (Venter 2007). However, there is little anatomical variation in the subfamily. Although mucilage cells are particlarly common in Scilloideae, they also seem to occur elsewhere (Lynch et al. 2006).

Taxa that have tepals with single vascular traces are common in Scilloideae. Wunderlich (1937) described the endosperm as being both helobial and nuclear in Hyacinthineae. Chromosome length can be bi- or even trimodal in the one karyotype. The leaves of seedlings are two-ranked.

Information is taken from Speta (1998a: subfamilial classification of Hyacinthaceae, 1998b: general), 2001 (subfamilial characters) and Pfosser and Speta (1999); for chemistry, see Kite et al. (2000) and Pfosser and Speta (2001), for some embryology, see Eunus (1950) and Berg (1962), for floral morphology in Ledebouriinae, see Lebatha and Buys (2006), and for the cytology of some sub-Saharan members, see Goldblatt and Manning (2011).

Phylogeny. There is little well-supported structure along the backbone of what are here called Hyacintheae and again within Hyacinthineae in the trnL-F spacer analysis of Wetschnig et al. (2002); the positions of Ornithogaleae and Urgineeae were also unclear. The topology [Oziroëeae [Ornithogaleae [Urgineeae + Hyacintheae]]] has moderate support in Manning et al. (2004). For phylogeny, see also Pfosser et al. (2003) and the recent papers dealing with classification of parts of the subfamily.

Classification. Note that there is considerable disagreement over generic limits in Scilloideae; are there 15 or 45 genera in sub-Saharan Africa? (e.g. Stedje 2001a, b; Pfosser & Speta 2001; Lebatha et al. 2006). See Speta (1998a) for the dismemberment of Scilla and Martínez-Azorín et al. (2011) for the dismemberment of Ornithogaleae - 19 genera, of which 11 replace Ornithogalum, perhaps recognizability of taxa is not quite the issue. Manning et al. (2004) provide a generic synopsis of the family in sub-Saharan Africa that integrates some morphology with relationships; like them, I have taken a generally broad view of genera. However, there are unresolved issues that include sampling, whether or not floral syndromes distort ideas of relationships (and so what effect characters taken from these syndromes have in combined analyses), the consequences of maintaining well-known generic names like Albuca and Galtonia as knowlege of phylogeny becomes clearer, and the role cytological data should play. As to Albuca, the genus is recognized in the recent reclassification of Ornithogaloideae by Manning et al. (2009).

See Guaglianone and Arroyo-Leuenberger (2002) for a revision (and distribution map) of Oziroëe.

Previous Relationships. Chlorogaloideae, until recently included in Hyacinthaceae/Scilloideae (e.g. Pfosser & Speta 1999), are here included in Agavoideae. The homoisoflavanones found in Scilloideae are rather uncommon in flowering plants, but they are also to be found in Camassia (Agavoideae, ex Chlorogaloideae) and Ophiopogon (Nolinoideae).

4. Agavoideae Herbert   Back to Asparagales

Plant rhizomatous; endosperm helobial, thick-walled, pitted, hemicellulosic.

23/637 - five groups below. More or less world-wide, esp. S.W. North America, few in Malesia, N. Australia, not cold temperate, New Zealand, etc. (map: see Ying et al. 1993; García-Mendoza & Galván V. 1995; Fl. N. Am. 26: 2002; Seberg 2007).

4A. Anemarrhena

Leaves ?spiral, base?; inflorescence a subspicate panicle; T ± free; A 3, opposite and adnate to middle of inner T; ovules 2/carpel, apotropous; seeds angled; embryo curved; n = 11; hypocotyl 0.

1/1: Anemarrhena asphodeloides. N. China, Korea.

Ubisch bodies are present in Anemarrhena, so there is probably a glandular tapetum. Information is taken from Conran and Rudall (1998 - confusion over stamen position) and Rudall et al. (1998b); Anemarrhenaceae were included in Anthericaceae (Agavoideae-Anthericum below) by Takhtajan (1997).

Synonymy: Anemarrhenaceae Conran, M. W. Chase & Rudall

Agave, etc. + Behnia + Herreria, etc. + Anthericum, etc.: (vessels in stem); nucellar cap, hypostase +.

This group has 100% support in three- and four-gene trees (Chase et al. 2000a; Fay et al. 2000; Bogler et al. 2006).

Agave, etc. + Hesperocallis: seeds flattened [?all]; n = 24, 30, chromosomes 0.4-10 µm long, bimodal [4-6 long, rest short]; karyotype duplication.

4B. Agave, etc.

Also caulescent, (bulbs, tunicated or not), leaves often fleshy; non-protein amino acids, saponins, (homoisoflavanones - Chlorogaloideae), flavonols +; stem secondary growth +; adaxial bundles in leaf inverted [?level]; also styloids +; (stomata para- or tetracytic), cuticular wax rodlets parallel; leaves spiral, (petiolate; vascular bundles inverted; margins serrate), apex (pungent-)pointed, base ?; inflorescence usually branched, and/or flowers in pairs or fascicles, (pedicel articulated - Chlorogaloideae); flowers large, (monosymmetric); tapetal cells several-nucleate; pollen semitectate, (operculate); ovary superior to inferior, (styles +; with 3 canals - Camassia), stigma wet to dry; ovules many/carpel, outer integument (4-)9-14 cells across, parietal tissue absent-2 cells across, (nucellar cap 2 cells across), ± postament, hypostase, obturator +; (capsule septicidal - some Yucca; berry), T marcescent; (endosperm thin-walled; perisperm +, oily - Yucca, Agave); (cotyledon non-photosynthetic - Funkia), hypocotyl to 4 mm long, collar rhizoids +, primary root often branched.

10/340: Agave (210), Yucca (50). Central U.S.A. to N. South America, mostly S.W. North America, also East Asia (Hosta). [Photo - Flower]

Synonymy: Agavaceae Dumortier, nom. cons., Chlorogalaceae Doweld & Reveal, Funkiaceae Horaninov, nom. illeg., Hesperocallidaceae Traub, Hostaceae B. Mathew (endosperm cells thin-walled), Yuccaceae J. Agardh (perisperm +)

[Behnia [Herreria, etc. + Anthericum, etc.]]: ?

4C. Behnia

Secondary thickening +; tannin cells 0; velamen 1-layered; vessel elements also in the stem; leaves two-ranked, "supervolute", petiolate, with midrib and transverse secondaries, leaf base not sheathing; dioecious; T marcescent, not twisting; A adnate to base of T; ovules 2-3/carpel, micropyle?, parietal tissue absent; stigma 3-lobed, wet; fruit a berry; seeds angular, phytomelan 0, testa and tegmen thin-walled; endosperm walls not pitted and hemicellulosic; n = ?

1/1: Behnia reticulata. S.E. Africa.

Behnia was included in Luzuriagaceae (Liliales here) by Taktajan (1997), butit had also been placed in other families of that order and of Asparagales (Bogler et al. 2006); its broad leaves and campanulate flowers make it phenetically rather odd..

General information is taken from Conran (1998); details of ovules are unknown.

Synonymy: Behniaceae Conran, M. W. Chase & Rudall

[Herreria, etc. + Anthericum, etc.]: (stem secondary growth +).

4E. Herreria, Herreriopsis

Stems usu. climbing, prickly; saponins +, chelidonic acid?; (vessel elements in stem); mucilage cells 0; cuticular wax rodlets parallel; leaves ?spiral, ?cladodes, in fascicles, sheath?; pedicels not articulated; T and A free; ovules 1-many/carpel, parietal tissue?; fruit a septicidal capsule; seeds flattened; "embryo short"; n = 27, dimorphic [one large], chromosomes 0.7-3.7 µm long [Herreria]; "germination epigeal".

2[list]/9. South America (Brazil southwards), Madagascar. [Photo - Fruit]

The outer tepals of Herreriopsis have sac-like bases - possibly tepalline nectaries. The leaves are described as being cladode-like (Conran 1998) or cladodes (Stevenson in Takhtajan 1997).

Much information is taken from Conran (1998); the embryology is largely unknown.

Synonymy: Herreriaceae Kunth

5. Anthericum, etc.   Back to Asparagales

Rhizome short; chelidonic acid +; (velamen +); (vessel elements in the stems); mucilage cells +, tannin cells 0; cuticular wax rodlets parallel; leaves spiral to two-ranked, base sheathing; inflorescence thyrsoid (raceme); (pedicels not articulated); (flower monosymmetric), (T tube 0); (pollen mixed with raphides); stigma dry; ovules 2-many/carpel, outer integument ca 4 cells across; embryo sac haustoria common; T persistent in fruit; seeds angular or flattened, tegmen?; embryo curved or angled; n = 7, 8, 10, 11, 13-15, etc., chromosomes 2-10(-13.8) µm long, genome duplication [Chlorophytum]; cotyledon not photosynthetic, coleoptile + [Chlorophytum].

8/285: Chlorophytum (150 - styloids +), Anthericum (65), Echeandia (60). More or less worldwide, but not cold temperate, few in Malesia, N. Australia, not New Zealand, etc. [Photo - Inflorescence] [Photo - Flower]

Synonymy: Anthericaceae J. Agardh

Evolution. Divergence & Distribution. Good-Avila et al. (2006) suggest that Agave et al. are only some 26-20 million years old, and Yucca 18-13 million years old; Wikström et al. (2001) give an age for the whole Agavoideae of some 35 million years before present that is also fairly recent compared to the first set of dates. Rocha et al. (2006) suggest ca 12.75 million years for the age of Agave etc. and ca 10.2 million years for Agave s.l. (Hesperaloe and everything above in the tree - Bogler et al. 2006; cf. also Smith et al. 2008); there are yet other possibilities for dates. Pulses of diversification in agaves may be considerably younger, being a mere 9-6 million years ago, a time when other succulent clades were diversifying (e.g. Good-Avila et al. 2006; Arakaki et al. 2011).

Floral Biology & Seed Dispersal. For information on the Yucca-yucca moth (Tegeticula, Prodoxidae) association, a textbook example of mutualism, which may be some 40 million years old (cf. the dates above), see Pellmyr et al. (1996, 2007), Pellmyr and Leebens-Mack (1999), Pellmyr (2003), Gaunt and Miles (2002) and Althoff et al. (2006); there may have been another and more recent radiation of yucca moths only 3-2 million years ago. Note that close relatives of yucca moths are also found on Dasylirion and Nolina (Nolinoideae, this page) and other Prodoxidae on Saxifragaceae (Saxifragales), and the ancestral condition for yucca mothsmay have been to eat ovaries (Yoder et al. 2010).

Good-Avila et al. (2006) discuss diversification in both Agave, which they suggest may be connected with the adoption of bat-pollination, and Yucca (see also Rocha et al. 2006). However, Smith et al. (2008) suggest that diversification was not significantly different in Yucca, with its 34 species, and Agave, with some 240 species.

Ecology & Physiology. Nobel (1988) discussed the eco-physiology of agaves and their relatives. In this part of Agavoideae over 300 species are succulents, mostly leaf succulents (Nyffeler & Eggli 2010b).

Chemistry, Morphology, etc. The raphides of Agave are hexagonal in transverse section. The flowers of Agave are shown with the median member of the outer whorl in the adaxial position (Spichiger et al. 2004). Camassia at least has single-trace tepals, Agave, etc. have three, while Hosta may have as many as 13 (Lin et al. 2011). In Polianthes the tapetal cells are multinucleate. In Hosta the stamens are sometimes inserted on the ovary. Germination of the pollen grain via the proximal pole has been reported in Beschorneria (Hesse et al. 2009a). Furcraea has nuclear endosperm.

Traub (1982) noted that Hesperocallis undulata smells of onions, and he even associated it with his Alliales. The genus was geographically odd in Hostaceae s. str., which is where other workers had placed it (cf. Kubitzki 1998b), but not in Agavoideae as here circumscribed; now Hosta is a little odd from the distributional point of view!

The ovary and fruit of Leucocrinum (Anthericum group) are below the surface of the ground (Bogler et al. 2006). At least some mitochondrial genes show an accelerated rate of change (G. Petersen et al. 2006). Some information is taken from Conran (1998); ovule morphology in the group is taken from Leucocrinum alone.

See Judd et al. (2007) for general information; for additional information, especially the part that has been considered Agavaceae s. str. in the past, i.e. Agave, Yucca and their immediate relatives, see Alvarez & Köhler (1987: pollen), Fagerlind (1941b), Cave (1948, 1955), Wunderlich (1950), and di Fulvio and Cave (1965), all embryology, Verhoek (1998: general), and McKain et al. 2011: genome duplication); see also Kubitzki (1998b - Hostaceae), Speta (1998 - Hyacinthaceae - Chlorogaloideae).

Phylogeny. For relationships within this clade, see Pires et al. (2004) and especially Bogler et al. (2006: 2- and 3-gene analyses, the latter with missing data, but overall the same topology). I have followed the latter - which see for more details - in the topology above. Support for the subfamily as a whole is only 75%, that for the [Behnia + Herreria, etc. + Anthericum, etc.] clade 87%, and that for [Herreria, etc. + Anthericum, etc.] only 51% (and less in the two-gene tree); however, other nodes have close to 100% support, and there is a fair amount of detail resolved in relationships around Agave and Yucca (see below). Largely similar relationships were found by G. Petersen et al. (2006c) in their analysis of variation of four mitochondrial genes that are evolving particularly quickly in this clade.

The circumscription of group 4b above, Agave etc., corresponds to that of Agavaceae s.l. in Bogler et al. (2006). Genera like Camassia, etc. (ex Hyacinthaceae - Chlorogaloideae) are included; note that these latter taxa have rhexigenetic lacumae (Lynch et al. 2006) like many Hyacinthaceae (Scilloideae) themselves. Hesperocallis undulata is sister to the rest of the Agave, etc., clade (Bogler et al. 2006). (In Smith et al. 2008 Agavaceae s.l. includes Hosta etc. and excludes Anthericaceae, although support for Agavaceae so delimited was weak, and that for the still broader circumscription adopted here was stronger.) For other phylogenetic work on this group, see Bogler and Simpson (1996: molecular) and Sandoval (1995: morphological).

Classification. The broad concept of Agavoideae adopted here may not seem very satisfactory, but I fear that none of the alternative solutions is much better when it comes to classifications and communication. Agave should probably include Polianthes, Manfreda, etc., see e.g. Bogler and Simpson (1995), Bogler et al. (2006) and Rocha et al. (2006). Paradisea (ex Asphodelaceae/Asphodeloideae) is to be included here in the Anthericum group (e.g. Chase et al. 2000b).

[Lomandroideae + Asparagoideae + Nolinoideae]: steroidal saponins +; pedicels articulated; fruit a capsule; endosperm helobial, thick-walled, pitted, hemicellulosic.

Phylogeny. There is moderate support for this clade in the four-gene chloroplast tree of Fay et al. (2000).

5. Lomandroideae Thorne & Reveal   Back to Asparagales

(Naphthoquinones +); (stem secondary growth +; vessel elements in leaves); (inner T fimbriate; T connate basally); (A adnate to tube); infra-locular septal nectaries +; nucellar epidermal and other cells enlarged, especially basally; antipodals cells large, inc. nuclei; T persistent in fruit; seeds rounded to angular; chromosomes 0.6-2.4 µm long [records incomplete]; cotyledon photosynthetic or not, (coleoptile +; first leaves reduced).

14-15[list]/178. Predominantly Australian, also Madagascar, India, South East Asia to the Pacific, and South America.

5A. Lomandra group

Tubers 0; lamina with sclerenchymatous ribs extending from the inner sheath of the vascular bundle to the surface, outer bundle sheath with enlarged cells; leaves two-ranked, flat or curved, (margins prickly), (base auriculate); pedicel articulated (not - Xerolirion); flowers long-lived; (pollen grains with encircling sulcus); stigma wet; ovules 1-2/carpel, nucellar cap +, nucellus with axially oriented central conducting passage; testa thin, tegmen brown, collapsed, cellular, phytomelan 0; endosperm hemicellulosic; n = 7-9, chromosomes 2-7 µm long.

5/65: Lomandra (50). Australia, New Guinea, New Caledonia. [Photo - Inflorescence © K. Stüber.]

Synonymy: Lomandraceae Lotsy

5B. Laxmannia group

Plant with (ecto)/vesicular-arbuscular mycorrhizae; storage roots +; mucilage +; leaves spiral, vernation supervolute or conduplicate, (petiolate), (ligulate); flowers single or in groups, long-lived, pedicel articulated or not; (anthers dehiscing by pores); stigma wet; nucellus with axial conducting tissue; (seed arillate), testa with phytomelan, exotesta often papillate, rest of testa cellular, tegmen thin; endosperm thin-walled; n = 4, 11, chromosomes 0.5-2 µm long.

8/92: Thysanotus (50), Arthropodium (20). South East Asia to Australia, New Zealand and the Pacific.

Synonymy: Eustrephaceae Chupov, Laxmanniaceae Bubani

5C. Cordyline group

Rosette herbs to trees; storage roots +; mucilage +; stomata paracytic, subsidiary cells witrh oblique divisions; leaves spiral, vernation supervolute or conduplicate, (pseudopetiolate); flowers single, pedicel not articulated; testa with phytomelan, anatomy?; endosperm ?; n = 3, 6, 19 (stamens dimorphic), chromosomes 0.5-2.4 µm long.

2/17. India to the Pacific and New Zealand, tropical America. [Photo - Habit, Flower.]

Chemistry, Morphology, etc. In Thysanotus, fungi are associated with the subepidermal layer of cells (McGee 1988).

The leaf of Lomandra and its relatives has sclerenchymatous ribs extending from the inner sheath of the vascular bundles (cf. also Cordyline?); in Dasypogonaceae this sheath is absent, in Xanthorrhoeaceae s. str. it comes from the mesophyll, although the leaves of all three are xeromorphic and superficially similar. The pollen of Lomandra is very variable, sometimes being spiraperturate (cf. Aphyllanthes). There is considerable variation in seedling morphology, even within individual groups (Conran 1998).

Some information is taken from Chanda and Ghosh (1976: pollen, as Xanthorrhoeaceae), Rudall and Chase (1996), Chase et al. (1996), Conran (1998, as Lomandraceae), and Rudall (1994b, 2000: ovule, etc.).

Classification. I have tentatively recognised three groups above, partly based on morphology, and partly based on molecular data (the Cordyline group - see Chase et al. 1996).

Xerolirion, from southwest Australia, has solitary, terminal carpellate flowers, staminate flowers in cymes, there is a single ovule per carpel, and it lacks silica bodies although there are cell wall ferulates; it is not entirely clear where it should be placed.

[Asparagoideae + Nolinoideae]: (velamen +); flowers rather small[!]; x = 10.

Chemistry, Morphology, etc. For phylloclade development in Asparagus and Ruscus and its relatives, see Cooney-Sovetts and Sattler (1987); for ovule development, see Rudall (1994b).

Baccate fruits containing seeds that lack phytomelan are common here, but I do not know at what level they might be apomorphic. Indeed, since the capsular Hemiphylacus and [Comosperma + Eriospermum] are respectively sister to other Asparagaceae and Ruscaceae, baccate fruits are probably derived (cf. Judd et al.).

6. Asparagoideae Burmeister   Back to Asparagales

Horizontal or vertical rhizome; flavonols, saponins +; vessel elements in roots often with simple perforation plates, vessels also in stem; cuticular wax rodlets parallel; leaves spiral (scarious and subtending phylloclades - Asparagus), leaf base not sheathing; (plant mon- or dioecious) inflorescence ± fasciculate or paniculate; T tube at most short; A basally adnate to T ,(3, opposite inner T, outer A staminodial); stigma wet or dry; ovules 2-several /carpel, outer integument ca 6 cells across, nucellar epidermal cells enlarged; embryo sac curved; fruit usu. a berry; seed rounded to ± angled; testa multiplicative, collapsing, exotesta massive, tegmen inconspicuous; endosperm cells thick-walled, pitted, embryo long; n = also 56, chromosomes 1-3 µm long.

2[list]/165-295: Asparagus (160-290!). Old World, but hardly in Australasia, also Mexico (map: from Hernandez S. 1995; Hultén & Fries 1986; FloraBase 2007; Seberg 2007; B. Ford pers. comm. 2011: ?Malesia). [Photo - Flower, Fruit.]

Evolution. Fukuda et al. (2005) discuss diversification in Asparagus; this seems to have been rapid and to have started in S. Africa.

Chemistry, Morphology, etc. Methyl mercaptans are known from Asparagus. The prophylls ("bracts") at the bases of the pedicels in Hemiphylacus are described as being lateral (Hernandez S. 1995). Hemiphylacus (G opposite inner T, fruit a capsule; n = 56) used to be placed in Asphodelaceae.

Some information is taken from Robbins and Borthwick (1925: ovule and seed), Kubitzki and Rudall (1998) and Rudall et al. (1998b).

Synonymy: Hemiphylacaceae Doweld

7. Nolinoideae Burnett   Back to Asparagales

Flavonols, (azetidine-2-carboxylic acid [non-protein amino acid]), saponins +; (vessel elements in roots with simple perforation plates), (vessels in the stem); (stem secondary growth +); (velamen +); (vessels in stem - many ruscoids); (vascular bundles amphivasal); also styloids +; cuticular wax rodlets parallel; leaves (scarious), spiral or two-ranked (opposite - Polygonatum oppositifolium), (petiolate; broad, venation reticulate), margins spiny or not, (leaf base not sheathing); inflorescence also racemose; (flowers 2-merous - some Maianthemum; T not connate, (to 13, corona + [Aspidistra]; with a single trace); (A adnate to base of tube; connate); pollen often inaperturate/diffuse sulcate; stigma (much expanded), wet; ovules 1-6(-many)/carpel, (micropyle endostomal), outer integument 2-8 cells across, parietal tissue 1-3(-4) cells across, (0, but lateral tissue), nucellar cap 0 (+), obturator [funicle or ovary wall] +/0, (chalazal vascular bundle branched), raphides +/0; (embryo sac bisporic, 8 nucleate; tetrasporic, 16-nucleate [Allium and Drusa types]), antipodal cells not persistent (+), (embryo sac haustorium - Dasylirion); fruit also a berry (± a drupe); seeds rounded (angled), (sarcotesta - Ophiopogoneae; testa 0 - Dracaena), phytomelan 0, (phlobaphene +); (endosperm nuclear); n = 5-7, 9, 18-21, chromosomes 0.5-19 µm long (bimodal); cotyledon not photosynthetic, (coleoptile +), primary root well developed, branched or not.

26/475: Dracaena (100), Eriospermum (100), Aspidistra (90), Polygonatum (60), Ophiopogon (55). N. hemisphere, esp. Southeast Asia-Malesia (Convallariaceae s. str.), Europe and the Near East (Ruscaceae s. str.), S.W. North America (Nolinaceae s. str.), Africa, esp. the Cape and S.W. (Eriospermaceae s. str.) (map: from Meusel et al. 1965; Hultén & Fries 1986; Perry 1994, incomplete). [Photo - Ruscus Flower, Eriospermum Flower © M. Elvin.]

Evolution. Floral Biology & Seed Dispersal. The flowers of Aspidistra, sometimes borne beneath the litter, may have a short corona at the apex of the perianth tube. They also often have a large, fungiform stigma, the anthers being hidden below the stigma in the perianth tube, or the anthers may converge towards the centre of the flower, in both cases easy access to the nectar apparently blocked. It has been suggested that these flowers are pollinated by amphipods (Conran & Bradbury 2007 and references) and/or fungus gnats; they look rather like flowers of Asarum and some Burmanniaceae. There are also more conventional sub-rotate flowers in the genus which have the stamens and stigma/style grouped in the centre, and some species have a dozen or more tepal lobes.

Vegetative Variation. Vegetative variation is particularly impressive. Nolina (ex Nolinaceae) has secondary growth and is tree-like, while the initiation of the vascular system in the rhizome of Ophiopogon is similar to that in palm stems (Pizzolato 2009). The leaf blades of some species of Eriospermum have the most remarkable enations on the upper surface. These include fungiform protrusions on the small, crisped, ovate and fleshy blade (E. titanopsoides), a much-branched structure to 12 x 7.5 cm on a much smaller blade (E. ramosum), a bundle of enations with stellate hairs (E dregei), and paired enations that look as if they should grace the helmets of the Valkyries (E. alcicorne: see Perry 1994 for more details). These may be adaptations for catching water from fog in the foggy deserts of Namaqualand (Vogel & Müller-Doblies 2011). Many other taxa, including Maianthemum, have more or less broadly elliptic leaf blades. Finally, Ruscus and its immediate relatives have cladodes, the flowers being born in the middle of a tough, more or less elliptical leaf-like structure. The prophylls are lateral or in some interpretations completely adnate to the axillary shoot, together they form an expanded cladode (Arber 1930). In any event, the leaves proper are small and scarious and subtend the cladode-like structures (cf. Asparagus above).

Chemistry, Morphology, etc. Convallarieae are monopodial. Dracaena and relatives have resin canals. The outer integument is only two cells thick, as in Bowiea. The absence of septal nectaries in some taxa of this group may be connected with the presence of prominent ovary wall obturators; the latter are possibly derived from the former. In Liriope, etc. (Ophiopogoneae), the seeds, with their fleshy testa (see above), are exposed early in development, so they are semi-gymnospermous. Finally, in Peliosanthes teta, the only species in Peliosanthes, the ovary varies from superior to inferior (Jessop 1976), although some recognise more species in the genus.

Ruscus and its immediate relatives also have chrysophanol in the roots; filaments connate, anthers extrose, in carpellate flowers the filaments of the staminodes almost completely enclose the gynoecium; embryo short; n = 20.

Additional information can be found in Stenar (1953) and Wunderlich (1950), both embryology, Björnstad (1970), Lu (1985), Tillich (1995: seed, etc.), Bogler and Simpson (1996: relationships of Nolinaceae, Dracaenaceae, etc.), Bos (1998: Dracaenaceae), Conran and Tamura (1998: Convallariaceae), Bogler (1998: Nolinaceae), Terry and Rudall (1998: Eriospermaceae), Yeo (1998: Ruscaceae s. str.), Rudall & Campbell (1999: floral morphology), Judd et al. (2002: general), Judd (2003: Ruscaceae S.E. U.S.A.) and Yamashita and Tamura (2004: chromosome evolution in Convallarieae).

Phylogeny Comosperma, ex Anthericaceae (= Agavoideae), comes here. It and and the very distinct Eriospermum (for which, see Perry 1994) are likely to be sister to the rest of the family; both have capsules and hairy seeds. Note, however, that the hairs on the seeds develop in different ways, and Comosperma has two tenuinucellate apotropous ovules/carpel, n = 20 vs. n = 7, etc., the two genera seemingly being unrelated (Rudall 1999). The poorly understood Peliosanthes may also be in turn sister to the rest of the family (molecular data alone, e.g. Jang & Pfosser 2002).

Classification. There has been debate over the generic limits of Maianthemum, however, a broad circumscription seems appropriate; there is little support for infrageneric groupings within the clade that also includes Smilacina and the combined clade itself is well supported as being monophyletic (Kim & Lee 2007; Meng et al. 2008). For information on Aspidistra and its remarkable flowers, see Hou et al. (2009) and references; there is a monograph in Li (2004).

Synonymy: Aspidistraceae Hasskarl, Convallariaceae Horaninow, Dracaenaceae Salisbury, Eriospermaceae d'Orbigny (hypocotylar tuber; leaf sometimes with enations; pedicels not articulated; fruit a capsule; testa hairy; endosperm 0, perisperm +, embryo massive; n = (5-)7 (9, 10); cotyledon unifacial, photosynthetic), Nolinaceae Nakai, Ophiopogonaceae Meissner (apotropous ovules), Peliosanthaceae Salisbury, Polygonataceae Salisbury, Ruscaceae M. Roemer, nom. cons., Sansevieraceae Nakai, Tupistraceae Schnizlein