EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline; primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, xylem exarch, branching endogenous; arbuscular mycorrhizae +; shoot apical meristem complex; 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 +; tracheid/tracheid pits circular, bordered; sieve tube/cell plastids with starch grains; phloem fibers +; stem cork cambium superficial, root cork cambium deep seated; nodes ?; stomata ?; leaf vascular bundles collateral; leaves spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral, veins -5(-8) mm/mm²; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores] +, 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, 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 duplication, mitochondrial nad1 intron 2 and coxIIi3 intron present.

MAGNOLIOPHYTA

Plant woody, evergreen; lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, cyanogenesis via tyrosine pathway [ANITA grade?], lignins derived from both coniferyl and sinapyl alcohols, containing syringaldehyde [in positive Maüle reaction, syringyl:guaiacyl ratio less 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; stem with 2-layered tunica-corpus construction; wood fibers and wood parenchyma +; reaction wood ?, with gelatinous fibres; starch grains simple; primary cell wall mostly with pectic polysaccharides; tracheids +; sieve tubes eunucleate, with sieve plate, companion cells from same mother cell that gave rise to the tube, the sieve tube with P-proteins; nodes unilacunar; stomata with ends of guard cells level with aperture, paracytic; leaves with petiole and lamina [the latter formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, vein endings free; flowers perfect, polysymmetric, parts spiral [esp. the A], free, development in general centripetal, numbers unstable, P not differentiated, outer members not enclosing the rest of the bud, smaller than inner members, A many, with a single trace, introrse, filaments stout, anther ± embedded in the filament, tetrasporangiate, dithecal, 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, binucleate at dispersal, trinucleate eventually, tectum continuous or microperforate, exine columellar, endexine thin, compact, lamellate only in the apertural regions, pollen germinating in less than 3 hours, tube elongated, growing at 80-600 µm/hour, with callose plugs and callose-based walls, penetrating between cells, siphonogamy, penetration of ovules within ca 18 hours, distance to first ovule 1.1.-2.1 mm, nectary 0, G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, [outer integument often largely subdermal in origin, inner integument dermal], micropyle endostomal, integuments 2-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte ?type, stylulus short, hollow, stigma ± decurrent, wet [secretory]; P deciduous in fruit; seed exotestal; double fertilisation +, endosperm ?diploid, cellular [first division oblique, micropylar end initially with a single large cell, chalazal end more actively dividing], copious, oily and/or proteinaceous, embryo cellular ab initio; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)_n]; whole genome duplication, 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 PHYA/PHYC gene pairs.

Possible apomorphies are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied. Furthermore, details of relationships among gymnosperms will affect the level at which some of these characters are pegged.

NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: vessels +, elements with scalariform perforation plates; nucleus of egg cell sister to one of the polar nuclei; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.

ASPARAGALES + COMMELINIDS: ?

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

ASPARAGALES Bromhead  Main Tree, Synapomorphies.

Chelidonic acid +; (velamen +); (dimorphic root hypodermal cells +); anthers longer than wide, tapetal cells bi- to tetranuclear, microsporogenesis simultaneous, style +; seeds exotestal, tegmen not persistent; endosperm helobial; mitochondrial sdh3 gene lost. - 16-24 families, 1122 genera, 26071 species.

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.

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. 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). (In the past, the genera of Boryaceae have often been included in Anthericaceae, as by Takhtajan [1997].) However, 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. 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. However, the topology of their tree differs considerably in detail from that below. All in all, however, 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 topology of relationships is adopted here. Note that this rather changes the characterisation of Asparagales, many characters now being best moved to the subbasal node in the clade (cf. versions 7 and younger of this site). Diversification in 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).

Asparagales commonly have Arum-type arbuscular mycorrhizae, while in Liliales these mycorrhizae are commonly Paris-type (see F. A. Smith & Smith 1997). Three-trace tepals are found in Orchidaceae, Amaryllidaceae, Iridaceae, Asphodelaceae (but not Kniphofia, Ashpodelus), Agavaceae, Agapanthaceae, and Hemerocallidaceae; one-trace tepals in Ruscaceae (but not Maianthemum stellatum), Alliaceae, Aphyllanthaceae, and Asparagaceae. Hyacinthaceae 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 (Hemerocallidaceae)). 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 (2003), 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).

Includes Agapanthaceae, Agavaceae, Alliaceae, Amaryllidaceae, Aphyllanthaceae, Asparagaceae, Asphodelaceae, Asteliaceae, Blandfordiaceae, Boryaceae, Doryanthaceae, Hemerocallidaceae, Hyacinthaceae, Hypoxidaceae, Iridaceae, Ixioliriaceae, Lanariaceae, Laxmanniaceae, Orchidaceae, Ruscaceae, Tecophilaeaceae, Themidaceae, Xanthorrhoeaceae, Xeronemaceae.

Synonymy: Asparagineae J. Presl, Asphodelineae Thorne & Reveal, Hyacinthineae Link, Iridineae Engler - Agavales Hutchinson, Alliales Traub, Amaryllidales Bromhead, Asphodelales Doweld, Asteliales Dumortier, Hypoxidales Reveal & Doweld, Iridales Rafinesque, Ixiales Lindley, Narcissales Dumortier, Orchidales Rafinesque, Tecophilaeales Reveal, Xanthorrhoeales Reveal & Doweld - Iridanae Doweld, Orchidanae Doweld - Orchididae Heintze - Crinopsida Horaninov, Orchidopsida Bartling

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); inflorescence racemose; flowers monosymmetric, resupinate, T free, A 3 [median of outer whorl and laterals of inner whorl], basally adnate to style, tapetal cells uninucleate, septal nectaries 0, ovary inferior, placentae branched, ca 1500+ tenuinucellate ovules/carpel, funicle not vascularised, style solid, stigma wet; seeds minute, phytomelan 0; fruit splitting down its sides, T deciduous; endosperm barely developing, embryo minute, undifferentiated, haustorial suspensor +.

880[list]/21,950 - five subfamilies below. World-wide. [Photo - Flower]

1. Apostasioideae Horaninov

Chemistry unknown; vessel elements simple; stomata tetracytic; leaves spiral, plicate; Apostasia not resupinate, T apiculate, carinate, (A 2, staminode +/0 - Apostasia; pollen operculate), (embryo sac bisporic - Allium type - Neuwiedia), micropyle bistomal, style solid; 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).

For anatomy, see Stern et al. (1993), for phylogeny, see Kocyan et al. (2004).

Poorly known. Apostasia, at least, may be a pollen flower (Vogel 1981).

Synonymy: Apostasiaceae Lindley, Neuwiediaceae Reveal & Hoogland

Vanilloideae [Cypripedioideae [Orchidoideae + Epidendroideae]]: C-glycosyl flavones, (saponins), 6-hydroxy flavonols +; (velamen +; tilosomes +); leaves spiral or two-ranked; flowers strongly monosymmetric; (tepal nectaries +), labellum strongly differentiated, the style and A almost completely congenitally fused [gynostemium], anthers to 2x as broad as long, pollen sticky, placentation parietal, ovules not fully developed at pollination, stigma asymmetrical; 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 [by massive expansion of the apical column/connective], "pollinia" soft, viscidium 0, (pollen in tetrads), (placentation axile), rostellum [ridge, part of median stigmatic lobe] +; (T persistent; fruit baccate)); seeds fusiform, crustose, exotestal [outer parietal wall well developed], tegmen persisting; endosperm to 16-nucleate; n = 9, 10, 12, 14-16, 18.

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

Relationships within Vanilloideae are becoming fairly well resolved (Cameron 2004; Cameron & Molina 2006; Pansarin et al. 2008). Pogoniinae (Erythrorchis - mycoheterotroph), Vanillinae, Galeolinae and Lecanorchidinae (mycoheterotrophs).

For reticulate venation, see Cameron and Dickison (1998), for general information, see Pridgeon et al. (2003).

Synonymy: Vanillaceae Lindley

Cypripedioideae [Orchidoideae + Epidendroideae]: ?

3. Cypripedioideae Kosteletzky

(Stomata paracytic); leaves conduplicate or plicate; 2 abaxial T of outer whorl connate, labellum saccate, A 2 [from inner whorl], staminode 1 [median member of outer whorl], pollen operculate, (in tetrads), tapetal cells binucleate, microsporogenesis successive?, (pollen operculate), median stigma lobe largest, (embryo sac bisporic, eight celled [Allium-type]; micropyle bistomal); (T abscising); 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]

For relationships, including also a morphological survey, see Albert (1994). Selenipedium has a hard, dark testa, although apparently it lacks phytomelan.

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]), pollen forming pollinia that are variously attached to sticky viscidium, pollinarium stalk variously formed from part of the anther [caudicula], epidermis of the rostellum [tegula] or apex of the rostellum [hamulus], microsporogenesis simultaneous [tetrads tetrahedral], 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 not abscising; tegmen not persisting; n = 9 or more [19 common].

4. Orchidoideae Eaton

Plant sympodial; mycoheterotrophs rare, stem/root tuber common; 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, apex acute, pollinia soft/sectile, staminodes reduced, (hamulus [pollinium stalk from modified apical part of rostellum] +).

208/3630: Habenaria (600), Caladenia (250), Platanthera (200), Pterostylis (200), Disa (175: many from the Cape Region, see Bytebeier et al. 2007), Cynorkis (125), Orchis (125), Corybas (120), Goodyera (80-100), Satyrium (90: van der Niet & Linder 2008), 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).

Orchidoideae include Spiranthoideae; there the anther is incumbent and with apical rostellar tisssue. Rhizanthella is a subterranean mycoheterotroph. Pollination of some South African Coryciinae is by oil collecting bees; the flowers have paired, pouch-like structures like those of another local oil plant, Diascia (Scrophulariaceae: Pauw 2006). Ophrys is well known for its distinctive and variable labellum and production of chemicals like pheromones which mimick female insects: pollination is by pseudocopulation. Current estimates of species numbers in the genus range from 16 to 215, but the former number seems much closer to "reality" (Bateman et al. 2006a).

Relationships within Orchidoideae are becoming fairly well resolved (e.g. Cameron 2004); see Górniak et al. (2006) for Spiranthinae. Clemens et al. (2002) clarify relationships of the Diuridae, a few of which are to be placed in Epidendroideae, while Codonorchis may be even be sister to Epidendroideae and Orchidoideae combined.

For information, see Stern (1997a, b: anatomy), Stern et al. (1993a: anatomy), and Pridgeon et al. (2001a, 2003: general).

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

5. Epidendroideae Kosteletzky

Epiphytes common, (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, conduplicate (plicate), articulated with sheathing base (not); anther incumbent (strongly convex) [by column elongation, or by early anther bending (vandoids)], with beak, operculate, pollinia hard (sectile), apical part of median stigma lobe forms stipe [= pollinium stalk]; (cotyledon visible).

650/18000: Bulbophyllum (2035), Epidendrum (1500), Dendrobium (1400, but see below), Pleurothallis (1000), Lepanthes (>800), Stelis (700), Oncidium (680, but generic limits?), 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: major photosynthetic organs are green, flattened roots), Phreatia (160), Pinalia (160), Octomeria (150), Dracula (120), Encyclia (120), Dichaea (110), Trichosalpinx (110), Ceratostylis (100), Catasetum (100), Elleanthus (100), Glomera (100), Prostheacea (100), Sobralia (100), Camaridium (80), Platystela (75), Brachionidium (65), Appendicula (60), Callostylis (60), Neottia (60), Nervilia (60), Podochilus (60), Scaphyglottis (60), Sophronitis (60), Ornithidium (55), Lepanthopsis (50), Maxillariella (50), Restrepia (50). More or less world-wide, but most diverse in the tropics; rather poorly developed in Australia (Map: from Pridgeon et al. 2005).

Many of the epiphytic Epidendroideae, perhaps some 7,000 species, are likely to have crassulacean acid metabolism (Winter & Smith 1996b). Chase and Palmer (1997) discuss evolution of the minute twig epiphytes in Oncidiinae. Vandeae are monopodial, and taxa lacking photosynthetic leaves, or with very deciduous leaves, but having photosynthetic roots (rarely the stem is photosynthetic) have evolved several times; over 200 species, all epiphytes, are involved (e.g. Carlsward et al. 2003). In addition to the pneumathodes of other Epidendroideae, they have aeration units, and distinctive exodermal cells and associated cortical cells (Carlsward et al. 2006a, b). CAM photosynthesis is common in these plants, but how carbon dioxide and water flux are controlled is unclear; there are no stomata (Cockburn et al. 1985).

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). Malaxis and Liparis may not be monophyletic, but are closely intertwined; it is likely that they are secondarily terrestrial. Generic limits here as elsewhere were based on floral variation, but vegetative variation correlates better with clades evident in molecular phylogenies (Cameron 2005a), even if anatomical variation may suggest little in the way of major phylogenetic structure (Stern et al. 2004; Stern & Carlsward 2006). 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), Clemens (2006) suggests a wholesale reorganization; note that the species numbers above do not reflect this (but cf. Burke et al. 2008 for an alternative view of how things should be reclassified). For a major study of Pleurothallidinae, see Pridgeon et al. (2001b; Pridgeon & Chase 2001 for a reclassification); Pleurothallis itself is also not monophyletic; Abele et al. (2005) and Matuszkiewicz and Tukallo (2006) discuss the phylogeny of Masdevallia (Pleurothallidinae). For general phylogenetic relationships in Epidendroideae, see van den Berg (2005), for 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), Oncidiinae, Williams et al. (2001a, b, 2005), Stern and Carlsward (2006: anatomy), Cymbidieae, Whitten et al. (2005) and Cieślicka (2006: Eulophia), Epidendreae (Kulak et al. 2006), Mascarene angraecoid orchids, surprisingly diverse, but Reunion in particular with a diverse insect fauna (Micheneau et al. 2008), and Aeridinae, see Hidayat et al. (2005: probably widespread parallelism in characters used to delimit genera). For a general account of the subfamily, see Pridgeon et al. (2005).

For general phylogenetic relationships, see van den Berg (2005), for 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) and Williams and Whitten (2003), Stern et al. (2004: anatomy) and including Oncidiinae, Williams et al. (2001a, b, 2005), Stern and Carlsward (2006: anatomy), Cymbidieae, Whitten et al. (2005), and Aeridinae, see Hidayat et al. (2005: probably widespread parallelism in characters used to delimit genera).

• 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.

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), and the minimum ages estimates of Ramírez et al. (2007: calibration by Miocene Goodyerinae pollinaria found in amber) are somewhat younger, 87-76 million years before present. Ramírez et al. (2007) suggest that the subfamilies had diverged by the end of the Cretaceous, ca 65 million years before present (or perhaps early Palaeocene), with diversification in the speciose, epiphytic Epidendroideae being Eocene in age, perhaps 47-40 million years before present. (Wikström et al. [2001] suggest divergence between the single member of Cypripediodeae and Epidendroideae included in their analysis as being much younger, ca 37-36 million years before present.) However, although Orchidaceae are diverse, note that they are sister to the rest of Asparagales which are morphologically very diverse and include some 6,850 species, and Asparagales as a whole are sister to commelinids, with some 22,750 species. Numbers and sister-group relationships alone are not yet telling much of a story, indeed, we still know little about the origin and biogeography of the family (see also Chase 2003 for a convenient summary).

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 orchid seeds, etc. Some of the distinctive features of the family seem to be connected. Thus pollinia ensure the fertilization of numerous ovules; the minute seeds to which they give rise, usually devoid of endosperm or differentiated embryo, are well suited for wind dispersal; and the obligate myco-heterotrophy of the young plant may compensate for the absence of seed reserves (Johnson & Edwards 2000 in part).

Tremblay et al. (2005) review the evolutionary consequences of variation in sexual reproduction in orchids. Orchidaceae are of course noted for the diversity of pollination mechanisms they show; the flowers may be notably long-lived (months!), although some last only for a single day, and orchid diversification is often explained in terms of the close association between pollinators and individual species of orchids. Cozzolini and Widmer (2005) suggested more particularly that diversification is associated with the deceptive pollination so prevalent in the family; about one third of the species - some 6500 or so - are pollinated in this way (Schlüter & Schiestel 2008 for molecular mechanisms). The plesiomorphic condition for the family may be to lack nectar, pollen alone being collected from flowers of Apostasioideae. Nectaries do occur in Orchidaceae, and they vary in position although they are never septal; nectar is in fact a common reward (Bernadello et al. 2007 and references). However, some 8,000 species of orchids lack nectar altogether. Cozzolini and Widmer (2005) suggested more particularly that diversification is associated with the deceptive pollination so prevalent in the family; about one third of the species - some 6500 or so - are pollinated in this way (Schlüter & Schiestel 2008 for molecular mechanisms). Deceit pollination may under certain situations increase outcrossing and speciation, the latter because of the specificity of the pheromones produced by the plants (Jersáková et al. 2006; see also Ledford 2007). Perhaps 60% of orchids are pollinated by bees (Schoonhoven et al. 2005), deceived or otherwise. The European Ophrys (Orchidoideae) is well known for its distinctive and variable labellum and production of chemicals like pheromones which together allow the flower to mimick female insects: pollination is by pseudocopulation by bees and wasps in particular. Alkenes (hydrocarbons with at least one double bond) are involved in the chemical component in this mimicry, and such chemicals are common in related genera as well (Schiestl " Cozzolino 2008). (Note that current estimates of species numbers in Ophrys range from 16 to 215, but the former number seems much closer to "reality" [Bateman et al. 2006a; Devey et al. 2008].) Flowers of Serapias (Bellusci et al. 2008 for a phylogeny) may even attract pollinators by mimicking a nest hole. Within Epidendroideae, pollination during pseudocopulation with fungus gnats has recently been reported in the large genus Lepanthes (Blanco & Barboza 2005). It has been suggested (based on work on European orchids) that in those orchids with generalized food-deceptive mating mechanisms, barriers to crossing may be postzygotic, whereas those that practice sexual deception have premating reproductive barriers (Cozzolino & Scopece 2008). Although artificial hybrids involving three or more genera have been reported, how these will look when generic boudaries are redrawn is unclear, nevertheless, many Orchidaceae can be crossed artificially, perhaps because of the presence of well-developed premating barriers alone.

Pollination of some South African Orchidoideae-Coryciinae is by oil-collecting bees; the flowers have paired, pouch-like structures like those of another local oil plant, Diascia (Scrophulariaceae: Pauw 2006). Orchids in Oncidiinae have elaiophores, sometimes on the labellum, and may be mimics of Malpighiaceae, both being visited by bees like Centris, etc. (Stpiczyńska & Davies 2008). The distinctive 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). Williams (1982) discussed the general importance of 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, especially those growing at lower altitudes - ca 2,000 species may be so pollinated (Cameron 2004 and references [Photo: Pollinators.]) - not to mention hundreds of species of Zingiberales, Gesneriaceae, Lecythidaceae, etc. Although effective pollinators, the relationships between orchids and euglossine bees are non-specific on both sides (Cameron 2004). Examples of butterfly, moth and even bird pollination are also well known. Thus 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; Xanthopus morgani praedicta, with a proboscis length of ca 25 cm, was subsequently discovered (Nilsson et al. 1987; Nilsson 1988). Normally neither orchids nor 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). For a summary of pollination in Orchidaceae, see van der Cingel (1995, 2001).

Members of Orchidaceae are not often eaten by butterfly caterpillars (Janz & Nylin 1998), although Riodininae-Riodininae larvae may be found on them (Hall 2003 and references).

There is a close association between basidiomycete - and perhaps some ascomycete - fungi (see Currah et al. 1997 for a list of the fungi, Rhizoctonia is a common anamorph or form genus; Otero et al. 2002) and orchids that starts with germination of the latter; 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. More importantly, details of the fungus-orchid association are particularly unclear in Apostasioideae, although the basiomycete Tulasniella is involved, as in Cypripedium, etc. (Kristiansen et al. 2004). Stomatiferous root tubercules form in Apostasia as a result of the association with the fungus, and it has been suggested that 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. 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 seeds being as little as 150 µm long or less. The specificity of the mycorrhizal association with fungi may be connected with the diversification of the family (Otero & Flanagan 2006), although the relationship is by no means one-on-one. Obligate mycoheterotrophy is not uncommon, a number of orchids having independently become achlorophyllous mycoheterotrophs; this may have happened some 20 times in the family (Molvray et al. 2000), although the fungi involved are different. In Corallorhiza (Epidendroideae) the fungi involved are several species of Russula which form an ectomycorrhizal association with adjacent trees and an endomycorrhizal association with the orchid (Taylor & Bruns 1999). However, bidirectional movement of carbon has been detected even in chlorophyllous orchids (Cameron et al. 2008).

Orchidaceae show considerable diversity in habit, given their generally modest size. In Vandeae, taxa lacking photosynthetic leaves, or having very deciduous leaves, but having photosynthetic roots (rarely the stem is photosynthetic) have evolved several times - the aptly named Taeniophyllum with its distinctive flattened photosynthetic roots is one example (e.g. Carlsward et al. 2006b). The epiphytic habit is particularly common in Epidendroideae, indeed, about 70% of Orchidaceae are epiphytes, a habitat in which they have to deal with periodic drought and lack of nutrients (Gravendell et al. 2004, see also Motomura et al. 2008). Indeed, preliminary analyses suggest that speciation increases in epiphytic clades (Gravendeel et al,. 2004). Twig epiphytes in particular grow in extreme conditions, and some minute twig epiphytes of the Epidendroideae-Oncidiinae mature within a year (Chase 1987; Chase and Palmer 1997). Particularly in New World epiphytic Epidendroideae there are 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); such cells are also found in ground-dwelling Orchidoideae-Spiranthinae (Figueroa et al. 2008). Fay et al. (2006a) suggest that epiphytism is associated with a small to moderate genome size. Extrafloral nectaries are scattered in the family, and they can be found on the stems opposite the leaves in Vanilla, at the bases of the pedicels in Cymbidium, etc.

Generic limits in the family are in the middle of a major overhaul to make them consistent with molecular findings. In many cases it is clear that floral differences were over-emphasized in the past, the features characterising the erstwhile broadly-delimited and polyphyletic Oncidium - basically, mimicry of Malpighiaceae oil flowers - being just a single example (Williams et al. 2001; Neubig et al. 2008), and there is widespread homoplasy in such floral features. It is thus unsurprising that generic limits suggested by molecular studies and those suggested by variation in floral morphology do not always agree (Kocyan et al. 2008 and references), indeed, in some cases vegetative variation may correlate better with clades evident in molecular phylogenies (e.g. Cameron 2005a). On the other hand, Szlachetko et al. (2005 and references) give a statement of the "floral" position, maintaining that variation in column form, etc., yields taxonomically important characters.

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). Flowers of Orchidaceae may be variably resupinate along an arching inflorescence, the end result being that all flowers of the inflorescence are held vertically resupinate, with the ovary sometimes 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 mechanism involved - that flowers in the speciose Bulbophyllum present themselves. In other orchids such as Calopogon the flowers are not resupinate, and all flowers on the erect inflorescence show "normal" monocot orientation. In the dioecious Catasetum resupination varies between staminate (resupinate) and carpellate (not resupinate) flowers (the latter can also be 20 times as big as the former); staminate and carpellate specimens were once placed in separate genera, Myanthus and Monachanthus respectively. The ovules are usually not fully developed at anthesis, and 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, see also 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).

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). Prutch and Schill (2000) discuss variation in the morphology and ultrastructure of the stigma; variation seems to be at about the subfamilial level. There is much variation in chromosome number and size. Thus Apostasioideae and Orchidoideae have small chromosomes, while larger chromosomes occur in Cypripedioideae and Vanillioideae. 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).

There is 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). 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]). This hypothesis is followed here, and it suggests that the monandrous condition may have evolved twice (see also Freudenstein et al. 2002). (A conservative topology might be that of a polychotomy [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).

Information is taken from Swamy (1948: floral vasculature), Wirth and Withner (1959: embryology and development), van der Pijl and Dodson (1966: pollination), Rasmussen (1982: pollinarium morphology), 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), Pridgeon et al. (1999), Rasmussen (1999: terrestrial orchids), Kurzweil (2000), Molvray et al. (2000), Cameron and Chase (2000), Johnson and Edwards (2000: pollinia morphology), Freudenstein and Rasmussen (1997: sectile pollinia, pollinia that separate into groups of pollen grains), Szlachetko and Rutkowski (2000: gynostemium), Kocyan and Endress (2001a: floral development), Kristiansen et al. (2001), Johansen and Frederiksen (2002: flowers), Cameron (2002), Szlachetko and Margonska (2002: gynostemium), Kurzweil (esp. 1987, 1993: floral development), Kurzweil and Kocyan (2002: a general survey of floral development), Freudenstein et al. (2002: pollinium development, 2004: phylogeny), Prychid et al. (2004: SiO₂ bodies), Yeung (2005: embryogeny) and Cameron (2007: summary of phylogenetic studies). Chase et al. (2003) provide a higher-level phylogenetic classification for the family, while Govaerts et al. (2003) give a provisional checklist of the family (see also World Checklist of Monocots).

Boryaceae et al. + Ixoliriaceae, etc. + Doryanthaceae + Iridaceae + Xeronemaceae + Hemerocallidaceae, etc., + Alliaceae, etc., + Asparagaceae, etc.: fructans +; cuticle wax crystals as parallel platelets; (T ± connate, A inserted on T tube); seeds exotestal, (phytomelan +).

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

Boryaceae [Blandfordiaceae [Lanariaceae [Asteliaceae + Hypoxidaceae]]]: ovules with hypostase, embryo sac with chalazal constriction.

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, many crassinucellate [parietal cell only] ovules/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.

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 coil-forming Rhizoctonia (cf. Orchidaceae); the plant is arborescent and dessication-tolerant (Barthlott 2006). The pedicels of Alania have several bracteoles. The nucellus is a single cell layer across.

Information is taken from Dahlgren et al. (1985), Conran (1998: general), Conran and Temby (2000: floral morphology).

Blandfordiaceae [Lanariaceae [Asteliaceae + Hypoxidaceae]]: ovules with hypostase, and nucellar cap.

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).

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, many ovules/carpel, outer integument ca 4 cells across, style short, stigma ± punctate, dry; 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]

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

Rudall (2003) suggested a close morphological relationship between Boryaceae and Blandfordiaceae.

Information is taken from Clifford and Conran (1998: general), Prakash and Ramsey (2000: embryology) and Kocyan and Endress (2001b: some floral morphology.

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

LANARIACEAE R. Dahlgren & A. E. van Wyk   Back to Asparagales

Plant with vertical rhizome; biflavones +; raphides 0 (styloids +); leaves two-ranked to spiral, sheath ?closed; inflorescence branched; T connate half-way, A adnate in mouth, G ± inferior, 2 apotropous fully crassinucellate ovules/carpel, micropyle zig-zag, integument ca 5 cells across, obturator +, style long, stigma punctate; capsule type?; seed 1; exotesta palisade, thin-walled, 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.

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

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 +; leaves spiral, base sheathing or not; (plant dioecious), 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 + (0 - Milligania), few to many ovules/carpel, micropyle also zig-zag, hypostase +, nucellar cap 0, style divided or not (short), stigmas dry; fruit a berry (capsule type Milligania?); (seed with mucilaginous hairs), no hemicellulose; n = 8, 30, ?35, chromosomes 4-6 µm long; seedling primary root well developed.

2-4[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.]

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).

The nectaries may be on the outside of the ovary.

See Di Fulvio and Cave (1965) and Prakash and Ramsey (2000: both embryology), Bayer et al. (1998a: general), and Birch et al. (2008: generic limits, biogeography) for information.

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

Stem ± cormose, leaf bases persisting, contractile roots common; saponins 0; velamen +, dimorphic root hypodermis 0; stomata (tetracytic), with oblique or parallel cell divisions; leaves 3-ranked, (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), basifixed, sagittate, tapetum plasmodial, microsporogenesis successive [tetrads tetragonal], ovary inferior, apical beak common, (parietal - Empodium), septal nectary 0, few to many ovules/carpel, stigma ± radiate, dry or wet; fruit capsular (circumscissile) or baccate; seeds globose, 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, but apomictic...: ?inc. Rhodohypoxis, etc.). Seasonal tropics, esp. southern Africa (temperate) (Map: see Fl. N. Am. 26: 2002; FloraBase 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 tepal whorl 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.

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).

Kocyan (2007) found that some flowers of Curculigo racemosa were polyandrous, however, they were not fasciculate. There is controversy over variation in tapetum type and the numbers of cells in the nuclei, and whether or not there is a velamen. The ovules have a parietal cell, so are not tenuinucellate.

Rudall (2003) suggested that there was a close morphological relationship between Hypoxidaceae and Orchidaceae.

Some information is taken from Rudall et al. (1998a: anatomy), Nordal (1998: general), Judd (2000 general), and Kocyan and Endress (2001b: floral morphology).

Ixoliriaceae, etc. [Doryanthaceae [Iridaceae [Xeronemataceae [Hemerocallidaceae, etc. [Alliaceae, etc. + Asparagaceae, etc.]]]]]: ?

The divergence of thic clade (Asparagales + Iridaceae + Cyanastraceae) has been dated to ca 84 million years before present (Eguiarte 1995).

This clade is strongly supported in analyses using data from four plastid genes (Fay et al. 2000; see also Chase et al. 2000a), but no morphological characters have yet been found for it.

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

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 Doryanthaceae ([Ixoliriaceae + Iridaceae] are sister to Doryanthaceae in Chase et al. (2006), but with very little support), which are adjacent on the tree here.

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

Ixioliriaceae and Tecophilaeaceae are placed together (along with Eriospermaceae and Lanariaceae) in Takhtajan (1997).

IXIOLIRIACEAE Nakai   Back to Asparagales

Cormose; saponins 0?; dimorphic exodermis 0; peduncle with a sclerechymatous ring; mucilage cells +; leaf shortly cylindrical at apex, base ?type; inflorescence terminal, subumbellate, leafy; T tube short, A centrifixed, ovary inferior, many ovules/carpel, stigma 3-lobed, dry; seeds angled, phytomelan +; endosperm walls pitted, starch in cells surrounding embryo, embryo long; 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.

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

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

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

TECOPHILAEACEAE Leybold, nom. cons.   Back to Asparagales

Corm tunicate or not; ?saponins +; stomata paracytic, divisions parallel; (leaves petiolate, with midrib), sheaths open? (none); inflorescence a raceme, branched or not, or flowers axillary; flowers often monosymmetric, (T tube moderate), anthers ± poricidal, pollen operculate (not Kabayea and Cyanastrum), (stamens of very different sizes, or staminodes 2-3), G (semi-inferior; free - Cyanastrum), 2-many ana-campylotropous ovules/carpel, obturator +, stigma punctate; seed variable, phytomelan +/0, testa multilayered, (exotesta palisade), thick-walled; endosperm (nuclear - Cyanella), thick-walled, pitted or not, ?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.

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).

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 seedlings, which are variable in their morphology, from Tillich (1995, 2003).

Synonymy: Androsynaceae Salisbury, Conantheraceae (D. Don) J. D. Hooker, Cyanastraceae Engler, Cyanellaceae Salisbury, Walleriaceae (R. Dahlgren) Takhtajan

Doryanthaceae [Iridaceae [Xeronemataceae [Hemerocallidaceae, etc. [Alliaceae, etc. + Asparagaceae, etc.]]]]: ?

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

DORYANTHACEAE R. Dahlgren & Clifford   Back to Asparagales

Huge sub-bulbous tufted perennial; steroidal saponins +; styloids +, raphides 0; cuticular wax rodlets parallel, stomata paracytic; leaves spiral, when older with dry threads at apex; inflorescence a thyrse; T large, tube long, A further adnate to T, latrorse, centrifixed, endothecium thick, tapetal cells with several nuclei, pollen trichotomosulcate, ovary inferior, micropyle?, stigma punctate, dry; seeds flattened, testa many-layered, with phlobaphene; endosperm 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 having entire margins but disintegrating into fibres at the apex. Their subumbellate inflorescences borne at the end of long leafy stems have numerous large, radially symmetrical, bright red flowers with inferior ovaries.

The divergence of Doryanthaceae from other Asparagales can be dated to ca 107 million years before present (Janssen & Bremer 2004).

Rudall (2003) suggested a close morphological relationship between Iridaceae and Doryanthaceae.

Much information is taken from Clifford (1998); Tillich (2003) described seedling morphology. Kocyan and Endress (2001b) note that the connective is massive, the stamens being supplied by 2-4 "vascular complexes".

Iridaceae [Xeronemataceae [Hemerocallidaceae, etc. [Alliaceae, etc. + Asparagaceae, etc.]]]: (secondary thickening +); Arabidopsis-type telomeres lost, (TTAGGG)_n [human-type telomeres] common.

A group with quite strong support in Fay 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. Hyacinthaceae 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). Acanthocarpus also lacks the telomere, alone among the taxa discussed as being out-groups; in fact it is a member of Laxmanniaceae, an ingroup, not Dasypogonaceae.

IRIDACEAE Jussieu, nom. cons.   Back to Asparagales

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, isobifacial [edge on to the stem], plicate; flowers usu. large, T ± free, often aristate, A 3 (2 - Diplarrhena), extrorse, 1-many crassi- or tenuinucellate ovules/carpel, outer integument 4-6 cells across, micropyle endo- or exostomal, style branched (branches bifid), stigma on the edges of the complex/expanded style, dry; 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).

67[list]/1870 - eight subfamilies below. World-wide (Map: see Heywood 1978 [S. America], Hultén & Fries 1986; Fl. N. Am. 26: 2002; FloraBase 2005; Davies et al. 2005; Rodrigues & Sytsma 2006). [Photos - Collection]

1. Isophysidoideae Thorne & Reveal

Rhizome; vessels in roots with scalariform perforation plates; biflavonoids [amentoflavone] +; flower solitary, with spathes; microsporogenesis?, nectary 0, G [3], style shortly branched; seedling unknown.

1/1: Isophysis tasmanica. Tasmania.

Synonymy: Isophysidaceae F. A. Barkley

Iridoideae [Patersonioideae [Geosiridoideae [Aristeoideae [Nivenioideae + Crocoideae]]]]: xanthone [mangiferin] +; vessels in roots with simple perforation plates; inflorescence a rhipidium; (pollen operculate [often with two exine bands in a sulcus]), G inferior; endosperm nuclear.

2. Iridoideae Eaton

Habit various; gamma-glutamyl peptides, metacarboxy amino acids +; vessel elements in root with simple perforation plates; riphidia simple; flowers often last one day only; T nectaries +, oil glands or oil hairs +, (septal nectaries + - Diplarrhena), endothecium with spiral thickenings, style branches long, tubular; n = .

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

For diversification of the American Tigridieae, see Rodrigues and Sytsma (2006); there is very extensive floral homoplasy (as in Iris - Wilson 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. 2003); Diplarrhena also has spherical, inaperturate, intectate pollen grains.

Iris contains a greater diversity of isoflavonoids than any other group outside Fabaceae (Reynaud et al. 2005); for a phylogeny of the genus, see Tillie et al. (2001) and also Wilson (2004). Homeria and Moraea have bufadienolides (Harborne & Williams 2001). In Sisyrynchium and its relatives the style branches alternate with the stamens. For a discussion of the caruncles/arils of Iris, see Wilson (2006).

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] +; secondary growth +; flowers blue, last one day, (inner tepals reduced to scales or 0), filaments ± connate, pollen spherical, inaperturate, intectate; embryo small; n = 11, 21; two extra codons in rps4 gene.

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

Geosiridoideae [Aristeoideae [Nivenioideae + Crocoideae]]: ?

4. Geosiridoideae ("Geosiridaceae") Goldblatt & Manning

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

1/1: Geosiris. Madagascar, the Comores.

Aristeoideae [Nivenioideae + Crocoideae]: ?

5. Aristeoideae Vines

Plant rhizomatous; plumbagin +; flowers ± blue, usually last one day; T connate basally only, (nectaries +); embryo small; n = 16.

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

For plumbagin, see Harborne and Williams (2001); the genus is palynologically very variable, some members even having disulcate pollen (see Goldblatt & Le Thomas 1997; le Thomas et al. 2001).

Nivenioideae + Crocoideae: ?

6. Nivenioideae

Plant woody; secondary thickening +; unit of rhipidium with 1-2 flowers, flowers sessile; septal nectaries +; 1(-4) shield-shaped [tangentially flattened] seeds per loculus; n = 16.

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

Some species of Nivenia are heterostylous, a very uncommon condition in the monocots.

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; binate rhipidium with a single flower, flowers sessile, (last one day), obliquely monosymmetric or polysymmetric, endothecium with spiral thickenings, pollen exine tectate, perforate-scabrate, aperture with one or a pair of longitudinal bands forming operculum, septal nectaries +/0, ovules campylotropous, chalazal hypostase prominent; n = 9-17.

28/995: Gladiolus (260), Romulea (90: cytologically very variable, n = 9-17), Geissorhiza (85), Crocus (90: for a phylogeny, see Petersen et al. 2008, cf. in part Frello et al. 2004), Hesperantha (80), Babiana (55), Watsonia (50), Ixia (50). Overwhelmingly southern African, to Europe, Madagascar and Central Asia.

Within Crocoideae, Tritoniopsis (tubular cotyledonary shoot; tubular cataphyll) is sister to the rest, but with only moderate support; relationships between Gladioleae, Watsonieae, Freesieae, and Croceae are unclear (see especially Goldblatt et al. 2006 for details and classification).

The flowers of Gladiolus are obliquely monosymmetric, although this is hardly apparent in the open flowers dues to changes in orientation as the flower and inflorescence grow. Tepal patterning is usually to be found on an adaxial lateral member of the outer whorl and adjacent members of the inner tepal whorl, but it is sometimes occurs on the adaxial lateral and abaxial members of the outer whorl and tha single 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.

See Goldblatt and Manning (1998) for a treatment of much of Gladiolus. Goldblatt et al. (2004) discuss some relationships within Crocoideae.

Synonymy: Crocaceae Vest, Galaxiaceae Rafinesque, Gladiolaceae Rafinesque, Nivenioideae Goldblatt, Geosiridaceae Jonker, 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.

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. For radiation of the Cape genus Moraea, both cytologically and florally diverse, see Goldblatt et al. (2002); radiation in this and other genera may have begun in the Miocene some 25 million years before present.

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]). The flowers of Gladiolus are obliquely monosymmetrical, although this is hardly apparent in the open flowers dues to changes in orientation as the flower and inflorescence grow. Tepal patterning is usually to be found 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 tha single 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. All told, well over half the family has monosymmetric flowers of one sort or another; certainly, the evolution of monosymmetry in the family will repay further study (see also Davies et al. 2004b). In general 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). Babiana (Crocoideae) is pollinated by birds, scarab beetles, bees, moths, etc. (Goldblatt & Manning 2007).

There is also considerable variation in leaf 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.

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.

Iridaceae are monophyletic in nearly all studies (but cf. Chase et al. 1995a). Although the monotypic Isophysidoideae are sister to the rest of the family, and Crocoideae and Iridoideae appear to be monophyletic, the status of Aristeoideae is still 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 consideraly extended, or three more subfamilies will be needed. Goldblatt et al. (2008: five plastid genes) opted for this latter; they found strong support for the pectination basal to Crocoideae s. str., albeit using successive weighting, which tends to leave one a little uneasy. However, pending further work, I follow the classification suggested by Goldblatt er al. (200); the subtribes are for th most part well characterised.

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

Additional information is taken from from Rudall (1995a: anatomy), Goldblatt et al. (1998: general), Goldblatt (2001: general, and a classification on which the classification here is based), Reeves et al. (2001: phylogeny), Cocucci and Vogel (2001: nectaries), Tillich (2003a: seedlings - very variable), Rudall et al. (2003a: nectary evolution), and Goldblatt and Manning (2006: pollination, esp. in sub-Saharan Africa).

Xeronemataceae [Hemerocallidaceae, etc. [Alliaceae, etc. + Asparagaceae, etc.]]: mitochondrial rpl2 gene lost.

A strongly supported group in Fay et al. (2000). 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, isobifacial; 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.

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

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 (2003). Xeronemataceae were provisionally placed in Asphodelaceae by Takhtajan (1997) and in Hemerocallidaceae by Clifford et al. (1998).

Hemerocallidaceae, etc. [Alliaceae, etc. + Asparagaceae, etc.]: (pedicels articulated); septal nectaries infralocular [see beginning of this page], ovary superior.

This group has strong support in Fay et al. (2000) and Chase et al. (2000b). The optimisation of successive microsporogenesis is uncertain, i.a. microsporogenesis varies within the [Hemerocallidaceae + Xanthorrhoeaceae + Asphodelaceae].

Hemerocallidaceae [Xanthorrhoeaceae + Asphodelaceae] [= Xanthorrhoeaceae s.l.]: anthraquinones +; styloids +; cotyledon not photosynthetic.

Stem group Xanthorrhoeaceae s.l. are dated to ca 93 million years before present, divergence within crown group Xanthorrhoeaceae s.l. to ca 90 million years before present (Janssen & Bremer 2004).

A.P.G. II suggests as an option including all three families in Xanthorrhoeaceae s.l. There is variation in microsporogenesis in the clade.

There is strong support for this clade in Fay et al. (2000); see Kite et al. (2000) for the distribution of anthroquinones, McPherson et al. (2004) for taxa lacking the 3'-rps12 intron. However, relationships within it remain unclear. There is moderate support for [Xanthorrhoeaceae + Asphodelaceae] 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 [Xanthorrhoeaceae + Hemerocallidaceae] clade (see also Pires et al. 2006), while Chase et al. (2006, but see sampling) suggest a [Asphodelaceae + Hemerocallidaceae] clade. Both Hemerocallidaceae and Xanthorrhoeaceae have ovaries that are probably secondarily superior and that have infra-locular septal nectaries (Rudall 2002, 2003); Rudall (2003) suggested a close morphological relationship between Hemerocallidaceae and Asphodelaceae (and a relationship between Xanthorrhoeaceae and Iridaceae...).

HEMEROCALLIDACEAE R. Brown   Back to Asparagales

Habit various; flavonols, napthoquinones, saponins +; roots often swollen; mucilage cells 0; raphides 0; cuticular wax rodlets parallel; leaves (spirally) two-ranked, conduplicate to flat-conduplicate, keeled, the keel unifacial, sheath closed; 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), pollen usu. trichotomosulcate, infra-locular septal nectaries +, 1-many tenuinucellate ovules/carpel, nucellar cap +, chalazal nucellus well developed; endosperm usu. helobial, stigma dry (wet); fruit also a berry (nut, schizocarp); seeds ovoid, (with strophiole/aril); endosperm hemicellulosic, embryo also short; n = 4 [Agrostocrinum], 8, 9, 11, 12, chromosomes 0.8-17.3 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, and Africa (Dianella [25-350+ - see Carr 2007], Caesia). [Photo - Habit, Flower, Flower].

Loss of the 3'-rps12 intron characterises a major clade in the family (Johnsonieae + Hemerocallis + Simethis: McPherson et al. 2004; see also Chase et al. 2000b). Simethis used to be in Asphodelaceae.

Microsporogenesis in Hemerocallis was described as being successive (?alone in the family) 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 the family (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); in Hemerocallis, at least, this seems to be variable, and although flowers with the median outer tepal adaxial are common, the seal of the Daylily Society shows a flower with the normal monocot orientation.

Johnsonia has chelidonic acid (Ramstad 1953). The number of vascular bundles supplying the tepals varies from (1-)3-9(-25) (Clifford et al. 1998a).

Information is taken from Kosenko (1994: pollen), Chase et al. (1996: general), Clifford and Conran (1998 - Johnsoniaceae: general), and Clifford et al. (1998a: general).

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

Xanthorrhoeaceae + Asphodelaceae: secondary thickening +; A not adnate to T, hypostase +; seeds angled.

XANTHORRHOEACEAE Dumortier, nom. cons.   Back to Asparagales

Stem thick, woody; plant resiniferous; raphides 0; layer of sclerenchyma below epidermis in leaves; stomata paracytic; leaves spiral, unifacial, not sheathing; inflorescence spike-like, of congested cymes; pedicels not articulated; T = 3 dry + 3 subpetaloid, free, microsporogenesis successive [tetrads tetragonal], pollen extended sulcate, infra-locular septal nectaries +, several ovules/carpel, apex of nucellus pointed, stigma ± punctate, ?wet; 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.]

• Xanthorrhoeaceae can be recognised by their habit, having 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 erect, densely spike-like inflorescence with small flowers and capsular fruits.

The ovary seems to be secondarily superior (Rudall 2002). Floral tube? Chelidonic acid?

Information is taken from Chanda and Ghosh (1976: pollen), Rudall and Chase (1996: phylogeny) and Clifford (1998: general). For an ecological account of the group, see Lamont et al. (2004).

ASPHODELACEAE Jussieu, nom. cons.   Back to Asparagales

Geophytic herbs to pachycaul trees, rosette-forming; tetrahydroanthracenones in roots, steroidal saponins 0; (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 (leaves not sheathing); inflorescence (branched) racemose or spicate; pedicels articulated ["basal" clades] or not, ± weak monosymmetry common, T ± free (connate - Kniphofia, Alooideae, (anthers centrifixed), microsporogenesis simultaneous [tetrads tetrahedral], 1-many straight [atropous] [Asphodelus clade] to hemitropous [the rest] ovules/carpel, hypostase +, stigma dry (wet); (capsule fleshy); seed ± ovoid, with impressed funicular aril [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, bimodal; 3'-rps12 intron lost [Bulbine not sampled]; (coleoptile +).

Ca 15[list]/785: Aloe (400: generic limits need adjusting), Haworthia (70), Kniphofia (70, sp. limits difficult), Bulbine (60), Trachyandra (50). Africa, esp. South Africa, also South Africa + New Zealand (Bulbinella) and the Mediterranean to Central Asia (Map: see Reynolds 1966; Seberg 2007). [Photo - Collection, Inflorescence, Flowers.]

Within Asphodelaceae, Alooideae are very distinctive. 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 fibers 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); the recognition of Alooideae makes Asphodelaceae 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 Alooideae (4L + 3S: probably evolved independently, see Devey et al. 2006; Pires et al. 2006), and also the same medicinal properties... 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. Generic limits around Aloe itself are decidedly unsatisfactory (e.g. Treutlein et al. 2003).

Many species of Aloe and Haworthia are rosette plants with fleshy leaves, these can be spiral or distinctively two-ranked. As with Aizoaceae from southern Africa, there is great variation in the micromorphology of the epidermis (Cutler 1982).

Excremis coarctata (unsampled) is odd; it is 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 is sometimes included in Phormiaceae (= Hemerocallidaceae). The only other South American member of Asphodelaceae is Pasithea.

Aloin cells are reported from Dianella (Hemerocallidaceae: see Rudall et al. 2003a). Monosymmetry in e.g. Haworthia and relatives is rather weak.

Kniphofia has an bistomal micropyle and a nucellar endothelium (Takhtajan 1985); it lacks aloin cells, having a well developed sclerenchymatous cap in their place (as have some other Asphodelaceae, even some Alooideae). 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).

Three genera that used to be here in Asphodelaceae are now in Hemerocallidaceae (Simethis), Asparagaceae (Hemiphylacus) and Agavaceae (Paradisea, Anthericaceae s. str.) respectively - the evidence is largely molecular (Chase et al. 2000b).

Some information is taken from 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), Treutlein et al. (2003a, b: phylogeny), G. Smith and Steyn (2004: Alooideae), McPherson et al. (2004 - loss of the 3'-rps12 intron), and Reynolds (2004: esp. Aloe). I thank Syd Ramdhani and Matt Ogburn for useful discussion.

Synonymy: Aloaceae Batsch, Eccremidaceae Doweld

Alliaceae, etc., + Asparagaceae, etc.: microsporogenesis successive [possible place]; endosperm development?

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.

Microsporogenesis is uniform in this group. In those taxa from more basal clades also with 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).

A strongly supported group (e.g. Chase et al. 1995a; Fay et al. 2000; Chase et al. 2000b; Graham et al. 2005) - the core Asparagales. However, inclusion of Aphyllanthaceae tended to decrease support for clades in it (Graham et al. 2006). Furthermore, as we shall see, there is little morphological support for families or family groupings in the Asparagaceae area in particular.

Agapanthaceae [Alliaceae + Amaryllidaceae]: leaves two-ranked; inflorescence scapose, umbellate [cymose construction], with scarious spathe, inflorescence bracts 2 (or more - external), pedicels not articulated; (T free; A connate basally), (tapetal cells uninucleate), style long, stigma dry; endosperm nuclear or helobial; hypocotyl 0.

Stem group Alliaceae s.l. are dated to ca 91 million years before present, divergence within crown group Alliaceae s.l. begins ca 87 million years before present (Janssen & Bremer 2004). Fungi on Allium and other Alliaceae are rather different from those on Amaryllidaceae (e.g. Savile 1962).

Very large genomes with a C value of some 350 picograms or more are found in some Alliaceae and Amaryllidaceae - also also Hyacinthaceae and Orchidaceae (Leich et al. 2005).

Combining these three families into Alliaceae s.l. is an option in A.P.G. II.

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.

For tapetal cells, see Wunderlich (1954), for inflorescence structure, see Weberling (1989).

AGAPANTHACEAE F. Voigt   Back to Asparagales

Leaf ptyxis flat; inflorescence bracts connate along one side; flowers large, monosymmetric, T ± connate basally, ovules apotropous; seeds flat; endosperm with hemicellulose; n = (14) 15 (16), chromosomes 4-9 µm long; seedling as in Alliaceae?

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

• Agapanthaceae 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.

Information is taken from Kubitzki (1998b: general).

Alliaceae + Amaryllidaceae: geophytes, bulbs sympodial, tunicate, with contractile roots.

ALLIACEAE Borkhausen, nom. cons.   Back to Asparagales

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

13[list]/795: Allium (690). Mainly South America, but Allium esp. N. Temperate Eurasia - three groups below. [Photo - Collection] [Photo - Inflorescence, Flower, Flower.]

1. Allioideae Herbert

Bulbs lacking starch; (leaves ± unifacial); C basally connate, corona 0, A both basally connate and adnate to C, often with winged filaments, tapetal cells uninuclear, 2 epitropous-14 ovules/carpel, style solid, gynobasic; (caruncle +); endosperm cellular, embryo curved; n = (7) 8 (9).

1/260-780: nearly all Allium. North temperate, often seasonally dry, especially Central Asia, 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).

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), Friesen et al. (2006: phylogeny and subgeneric and sectional classification), and Nguyen et al. (2008: mostly west North American species, largely monophyletic). See Gregory et al. (1998) for Allium names.

Synonymy: Cepaceae Salisbury, Milulaceae Traub

Tulbaghioideae + Gilliesioideae: bulbs with starch; endosperm helobial.

2. Tulbaghioideae M. F. Fay & M. W. Chase

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

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

See Vosa (1975) for a revision and details of cytology.

Synonymy: Tulbaghiaceae Salisbury

3. Gilliesioideae Arnott

Corona +/0, (A 2-3; variously connate and adnate; extrorse; staminodes +), 2-many ovules/carpel; embryo short; n = ³4.

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

Gilliesia has very strongly monosymmetric flowers with two stamens; the flowers may mimic insects (Rudall et al. 2002). Schickendantziella has only three tepals; they are caudate. Nothoscordum has solid styles.

For the phylogeny of the group, see Fay et al. (2006b); part of Ipheion is embedded in Nothoscordum.

Synonymy: Gillesiaceae Lindley

• Alliaceae 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.

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. The flowers of Allium are shown with the median member of the outer whorl in the adaxial position (Spichiger et al. 2004). Do Alliaceae have apotropous ovules? There has been major movement of ribosomal protein and succinate dehydrogenase genes from the mitochondrion in Allium (Adams & Palmer 2003), and that genus has also lost its minisatellite telomeres (S&ygrave;korová et al. 2006).

Fay and Chase (1996) discuss relationships within the family; these show a topology of [Allioideae [Tulbaghioideae + Gilliesioideae]], although the support for the clades is rather weak; I follow their classification here.

Some information is taken from Berg and Maze (1966 - embryology), and Rahn (1998: general).

AMARYLLIDACEAE J. Saint-Hilaire, nom. cons.   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; corona +; A ± connate and with outgrowths or tepaloid webbing), ovary inferior, (outer integument 3< cells across), stigma capitate to deeply trifid, (wet); endosperm starchy or with hemicellulose (thin-walled), embryo poorly differentiated; 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.]

1. Amaryllideae J. Saint-Hilaire

Extensible [helically-thickened] fibers in leaf; leaves follow the flowers (perennial - many Crininae); A connate basally (not - Crininae; small appendages developed from filaments), pollen bisulcate, exine gemmate, with scattered spinules, intectate-columellate, ovules unitegmic, embryo sac Allium type, (style laterally displaced); seeds water-rich, non-dormant, testa to 25 cells thick, chlorophyllous, with stomata, or ± collapsed, with a corky layer, endosperm chlorophyllous, phytomelan 0; embryo chlorophyllous; (n = 10, 12, 15).

11/146: Crinum (65: for a phylogeny, see Kwembeya et al. 2007, flowers of some taxa monosymmetric), Strumaria (23). SubSaharan, especially South Africa, Crinum Pantropical.

Wind dispersal of the inflorescences is common; the rigid, radiating pedicels allow the inflorescences to bowl along. Seeds of Crinum can float and remain viable in sea water for two year.

Because of the leaf fibers, the coverings of the bulbs produce highly-extensible cotton-like fibers when torn. 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. 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.

Meerow and Snijman (2001, see also 2006) discuss relationships within this group and provide a classification for it; Amaryllis and Boophone are successively sister to the rest of the tribe. Note that the former genus differs from other Amaryllideae in not having a green testa, etc. Meerow et al. (2003) outline the phylogeny of Crinum, the only pantropical member of Amaryllidaceae.

Synonymy: Crinaceae Vest, Strumariaceae Salisbury

See Snijman and Linder (1996) for further information.

Cyrtantheae, etc.: bundle sheath cells parenchymatous.

2. Cyrtantheae Salisbury

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

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

Synonymy: Cyrtanthaceae Salisbury

Calostemmateae + Haemantheae: fruit indehiscent.

3. Calostemmateae D. & U. Müller-Doblies

2-3 ovules/carpel; embryo germinates precociously; fruit dry; phytomelan 0; n = 10.

2/4. Australia, Malesia.

The bulbil is the dispersal unit.