EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, apex multicellular, xylem exarch, branching endogenous; arbuscular mycorrhizae +; shoot apical meristem multicellular, interface specific plasmodesmatal network; stem with ectophloic eustele, endodermis 0, xylem endarch, branching exogenous; vascular tissue in t.s. discontinuous by interfascicular regions; vascular cambium + [xylem ("wood") differentiating internally, phloem externally]; wood homoxylous, tracheids +; 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 megaphyllous [determinancy evolved first, then ad/abaxial symmetry], spiral, simple, axillary buds +[?], prophylls [including bracteoles] two, lateral, veins -5 mm/mm² [mean for all non-angiosperms 1.8]; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores, i.e. no distal pore for release of gametes] +, grains mono[ana]sulcate, exine and intine homogeneous; ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, to ca 2 mm from receptive surface to egg, gametes two, 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 [N/O//A/C and P//BE lines], 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 in 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 a sieve plate and cytoplasm with P-proteins, companion cells from same mother cell that gave rise to the sieve tube; nodes unilacunar [1:?]; stomata with ends of guard cells level with pore, paracytic, outer stomatal ledges producing vestibule; leaves with petiole and lamina [the latter formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, veins (1.7-)4.1(-5.7) mm/mm², endings free; flowers perfect, polysymmetric, parts spiral [esp. the A], free, development in general centripetal, numbers unstable; P not sharply 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, ektexine columellar, endexine thin, compact, lamellate only in the apertural regions; 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, nucellus at apex of ovule 1-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte four-celled [one-modular, nucleus of egg cell sister to one of the polar nuclei], stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, dry [not secretory]; P deciduous in fruit; seed exotestal; pollen germinating in less than 3 hours, siphonogamy, tube elongated, growing at 80-600 µm/hour, with callose plugs and callose-based walls, penetrating between cells, penetration of ovules within ca 18 hours, distance to first ovule 1.1.-2.1 mm; tube moves between nucellar cells, 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, minute; 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 + C/PHYB + E gene pairs.

Evolution. Possible apomorphies for flowering plants are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable variation between families in particular for several of these characters, and also because details of relationships among gymnosperms will affect the level at which some of these characters are pegged. For example, if reticulate-perforate pollen is optimized to the next node on the tree (see Friis et al. 2009 for a discussion), it effectively makes the pollen morphology of the common ancestor of all angiosperms ambiguous... For other features such a a nucellus only one (Nymphaeales) to three cells thick above the embryo sac and a stylar canal lacking an epidermal layer, although plesiomorphous for basal grade angiosperms (Williams 2009), where on the tree a thicker nucellus and a stylar epidermal layer are acquired has not yet been indicated.

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

LAURALES Perleb  Main Tree, Synapomorphies.

(Cork subepidermal); sieve tube plastids with protein crystalloids; nodes 1:?; petiole bundle(s) arcuate; leaves opposite; inflorescence ± cymose; P spiral?, hypanthium +, inner staminodia +, 1(-2) basal ovules/carpel, archesporium multicellular, stylulus long, extragynoecial compitum +; fruitlets 1-seeded, indehiscent, hypanthium persistent; mesotesta crushed, endotesta tracheidal [seed endotestal], tegmen crushed; embryo long; duplication of the PI gene. - 7 families, 91 genera, 2858 species.

Evolution. Magallón and Castillo (2009) suggest that stem group Laurales are ca 198.2 and 127.7 million years old - relaxed and constrained penalized likelihood datings - and equivalent ages for the crown group are 171.4 and 119.3 million years.

Chemistry, Morphology, etc. Soltis et al. (2005b) summarize information on possible synapomorphies for the clade (see also Staedler et al. 2009). Isorhamnetin occurs in Lauraceae, Gomortegaceae and "Monimiaceae" (Crawford et al. 1986). The apex of the ovule in some Atherospermataceae is exposed, as may also occur in Siparunaceae and Calycanthaceae (Endress & Igersheim 1997). Little is known of obturator presence in the order, and of many other embryological details. Oginuma and Tobe (2006) suggest that the base chromosome number for the order is x = 11.

See also Metcalfe (1987) for anatomy, Endress and Igersheim (1997) and Eklund (1999) for general information, Kimoto and Tobe (2001) for embryology, and Renner (2005a) for information on diversification. I am grateful to S. Renner for comments.

Phylogeny. Calycanthaceae are sister to other members of the clade, but there is little other well-supported structure in interfamily relationships. Gomortegaceae + Atherospermataceae + Siparunaceae form a moderately-supported clade (relationships between the first two supported strongly in D. Soltis et al. 2000), Monimiaceae + Lauraceae + Hernandiaceae another (the last two had no support as sister taxa in D. Soltis et al. 2000), largely because of morphological data; the clade Hernandiaceae + Lauraceae has strong support (Doyle & Endress 2000, see also Renner & Chanderbali 2000). However, relationships between Monimiaceae, Lauraceae and Hernandiaceae are difficult to work out, this being one of the few cases where there seems to be persistent disagreement between morphology and molecules (Renner & Chanderbali 2000). Here I follow morphology, but molecular data may eventually carry the day (see Renner 2005a for the most recent study, for other phylogenetic work, see Renner et al. 1997 and Renner 1998, 1999).

Classification. The contents of Cronquist's (1981) Laurales and Takhtajan's (1997) Lauranae are largely the same as the Laurales as circumscribed here,

Includes Atherospermataceae, Calycanthaceae, Gomortegaceae, Hernandiaceae, Lauraceae, Monimiaceae, Siparunaceae.

Synonymy: Atherospermatales R. Brown, Calycanthales C. Martius, Gyrocarpales Dumortier, Hernandiales Blume, Illigerales Blume, Monimiales Dumortier - Lauranae Takhtajan - Calycanthidae C. Y. Wu, Lauridae C. Y. Wu - Lauropsida Horaninov

CALYCANTHACEAE Lindley   Back to Laurales

Deciduous or evergreen shrubs to trees; tryptamine [calycanth(id)ine] alkaloids +; primary stem ± with vascular cylinder; inverted and entirely distinct cortical bundles +; vessel elements with simple perforation plates; sieve tube plastids with fibers and starch; pericyclic fibers 0; nodes 1:2 [see below]; buds with scales; petiole bundle arcuate, with wing bundles; hairs unicellular; leaves with flat to curved ptyxis; flowers (terminal), large, cortical vascular system +; P many, deciduous, spiral; A connective prolonged, 10+ nectariferous staminodes, 1 (2) apotropous ovules/carpel, micropyle exostomal, outer integument 6-15 cells across, inner 4-5 cells, stigma dry; fruits ± achenial; testa multiplicative, exotestal cells cuboid, slightly lignified; endosperm lacking paternal contribution, 0.

5[list]/11 - two groups below. China, North America, N.E. Australia (map: from Wu 1983; Endress 1983; Hong 1993; Fl. N. Am. III 1997; Qian & Ricklefs 2004). [Photo - Fruit © Robert Kowal, Flower.]

1. Idiospermoideae Thorne

Flavonols 0, but luteolin, etc. +; (vessel elements with scalariform perforation plates); P ³10, filaments flattened; G 1-2(-5), outer integument 12-15 cells thick, nucellar beak +, stigma stout, fleshy, sessile [forming extragynoecial compitum]; cotyledons (3-)4, massive, peltate.

1/1: Idiospermum australiense. N.E. Australia.

2. Calycanthoideae Burnett

P 10³; A 5-18, filaments rather slender, (anthers valvate - Sinocalycanthus), pollen equatorially and vertically disulcate; G ³5, outer integument 5-6(-8) cells thick, stigma filiform, compitum by style coherence; cotyledons spirally twisted; n = 11, 12.

4/10. China, North America.

• Calycanthaceae can be recognised by their opposite, entire, exstipulate leaves that smell aromatic. The cortical bundles can be seen with a lens when the stem is cut, and they may also be visible externally as four, raised lines along the stem. The terminal bud often aborts. The large flowers have a bract-covered hypanthium; the inner members of the perianth secrete nectar or bear food bodies. The achenial fruits are attached to the inside of the rather dry hypanthium. [Photo - Flowers]

Evolution. Crown group Calycanthaceae may have started to diverge in the Campanian, ca. 110 million years ago (Zhou et al. 2006).

Fossils are interesting. Araipa florifera, from the Lower Cretaceous of Brasil, has flowers that externally are very like those of Calycanthaceae, but its leaves are lobed (Mohr & Ecklund 2003); unfortunately, nothing is known of the internal structure of the flower. The late Cretaceous Virginianthus calycanthoides (98-113 million years before present) has been placed in Calycanthaceae. It has small flowers, anthers dehiscing by lateral hinges, and reticulate pollen with a single sulcus (Friis et al. 1994). Its inclusion may change one or two ordinal/family group characters. Thus Idiospermum also has anasulcate pollen, and this may be plesiomorphic for the order, with disulcate pollen being an apomorphy for the rest of Calycanthaceae and inaperturate pollen for the rest of Laurales. Assuming the lateral hinges on the anthers of Virginianthus are equivalent to the rather differently oriented hinges found in most other taxa (but see also those of Sinocalycanthus - parallelism?), hinged anthers may be a synapomorphy for the order, and anthers with slits a synapomorphy for crown-group Calycanthaceae. However, the phylogenetic position of Virginianthus has been questioned, and whether it is in Calycanthaceae, sister to all other Laurales, or not even to be included in Laurales at all is unclear (Eklund 1999; Crepet et al. 2005; Zhou et al. 2006; Doyle & Endress 2007; Doyle et al. 2008b), although the latter idea is least likely. The rather younger (Turonian, ca 90 million years before present) Jerseyanthus is more certainly Calycanthaceae, and it may even be sister to Calycanthus; it has the distinctive disulcate pollen common in Calycanthaceae (Crepet et al. 2005). However, it is remarkable in having flower parts that from the outside are in the sequence petaloid tepal - introrse staminode - extrorse stamen - abaxially curved "petaloid staminode" - pistillode, an arrangement of parts quite unlike that of any other angiosperm, although Staedler et al. (2007) interpret the outer staminode series as being inner tepals.

Isozyme duplication in Calycanthus may suggest that this clade shows ancient polyploidy (Soltis & Soltis 1990).

Chemistry, Morphology, etc. The two rings of vascular bundles in the stem are quite distinct from the seedling stage onwards. The leaf is innervated by paired traces (which very soon fuse and form the median petiole bundle) from the inner series of bundles and then two traces from the cortical bundles that form the lateral or wing bundles (Beck et al. 1982), however, I could not see these central paired traces in Chimonanthus (material too much thickened?). Odd teeth are sometimes found on the lamina of Calycanthus virginianus, at least on the plant in my back garden. Calycanthus occidentalis has inverted recurrent vascular bundles in the hypanthium, perhaps evidence of receptacular epigyny (Dengler 1972). Staedler et al. (2007a) note that the numbers of floral parts, tepals, stamens, staminodes, etc., are more or less Fibonacci numbers (3, 5, 8, 13,....). The carpels in general are more or less plicate. The ovules of Calycanthus are close to tenuinucellate, but with a nucellar cap (Dahlgren 1927) and the micropyle is bistomal (Yamada et al. 2003). There is no triple fusion during fertilisation, and the endosperm develops autonomously. The seeds are poisonous and have characteristic alkaloids.

In morphology and anatomy, Idiospermum is similar to Calycanthaceae s. str., although the alkaloids and the distribution of xylem parenchyma differ in detail. For the morphology of Idiospermum, see Blake (1972), for chemistry, see Crawford et al. (1986).

For general information, see Nicely (1965) and Kubitzki (1993b), for the chloroplast genome, etc., see Goremykin et al. (2003b), for gynoecial development, see Staedler et al. (2007b), and for floral development in general, with suggestions of apomorphies for the two subfamilies in addition to those suggested above, see Staedler et al. (2009).

Phylogeny. Li et al. (2004) clarify phylogenetic relationships in the family; Idiospermum is sister to the rest.

Classification. Although Idiospermum is a very distinctive genus and has sometimes been recognised as a separate family (e.g. Cronquist 1981), it is monotypic and shares many features with the rest of the family.

Synonymy: Butneriaceae Barnhart, Chimonanthaceae Perleb, Idiospermaceae S. T. Blake

[Siparunaceae [Atherospermataceae + Gomortegaceae]] [Monimiaceae + Hernandiaceae + Lauraceae]: evergreen trees; vessel elements with scalariform perforation plates; hippocrepiform sclereids in pericycle; leaves with rather distant teeth, one vein entering opaque, persistent glandular cap; flowers rather small; A whorled, stamens with paired nectaries/glands at base, anthers bisporangiate/monothecal, valvate, valves apically hinged, tapetum ?, pollen inaperturate, ± spinulose, 1 ovule/carpel, ovule median, or early-initiated cross-zone, vascular bundle not branching in chalaza; (fruit with fleshy hypanthium/receptacle; hypanthium splitting irregularly).

Chemistry, Morphology, etc. Leitão et al. (1999) summarize alkaloid distribution in Monimiaceae in the old sense, which includes Atherospermataceae, Monimiaceae s. str., Siparunaceae and sometimes even Hernandiaceae. See Doyle (2007) for monimioid leaf teeth in this clade. Staedler and Endress (2009) discuss floral phyllotaxis; there is considerable variation, with whorled and spiral phyllotaxis occuring in all families that are not monotypic and phyllotaxis even varying within a species. There is also considerable variation in exine structure in this part of the tree, the pollen of many taxa having an infratectum that is more or less intermediate between granular and columellar (Doyle 2009).

There is little information on tapetal development, or of most other embryological details and of seed anatomy in this part of the tree; this is especially true of the first three families (see Kimoto & Tobe 2001 for a summary; Bello et al. 2002a for Siparuna). For information on Monimiaceae and the other families previously included in them, see Schodde (1970), Philipson (1993), Sampson (1993, 1997, 2007) and Foreman and Sampson (1987: pollen), Romanov et al. (2007: fruit anatomy) and Kimoto and Tobe (2008b: embryology).

Siparunaceae [Gomortegaceae + Atherospermataceae]: acicular crystals +; hypanthium closed by roof, pollen with columellar infratectum; embryo very small.

SIPARUNACEAE Schodde   Back to Laurales

Also lianes; plants Al accumulators; indumentum often stellate; vessel elements also with simple perforation plates; no hippocrepiform sclereids in pericycle; sieve tube plastids?; primary stem?; nodes 1:1; petiole bundles flattened-annular, (medullar plate +); cuticle wax?; leaves curved-conduplicate, (margins entire); plants monoecious or dioecious, P 4-6(-7) or obscure, calyptrate; A (1-)2-many [e.g. 2 + 2 + 2], paired glands 0, anthers often with one flap, tapetum secretory; G 3-many, occluded by secretion as well, ovule unitegmic, integument thick, (embryo sacs several, starch-rich, 1-nucleate, elongating - Siparuna), stylulus short; (drupelet with a fleshy appendage ["stylar aril"]), hypanthium fleshy, splitting; (seeds bilaterally flattened - Glossostigma), endotegmen with reticulate thickenings; n = 22.

2[list]/75: Siparuna (74). Tropical America (Siparuna), W. Africa (Glossocalyx) (map: S. Renner). [Photo - Flower] [Photo - Fruit]

• Siparunaceae may be recognised by their opposite, serrate, estipulate leaves with rather prominent brochidodromous venation; the wood lacks broad rays and the hairs are often stellate or fasciculate. The anthers lack basal glands.

Evolution. Dioecy seems to have evolved several times from monoecy in Siparunaceae (Renner & Won 2001). Pollination is by gall midges. In most taxa the hypanthium splits, the valaves spreading widely and exposing the drupelets inside. The fruitlets, or the fleshy appendage on the fruitlet, differ strikingly in color from the inside of the fruit (see also Monimiaceae). This fleshy appendage is called an aril by Renner and Hausner (1997) and occurs only in dioecious taxa.

Chemistry, Morphology, etc. The ovule is interpreted as having lost its outer integument by Kimoto and Tobe (2003); however, is the single integument better thought of as the outer integument? General information is taken from Philipson (1993) while details of embryology may be found in Heilborn (1931) and Kimoto and Tobe (2003) and of pollen development, etc., in Bello et al. (2002a).

Phylogeny. For phylogenetic relationships in Siparunaceae, see Renner and Won (2001).

Gomortegaceae + Atherospermataceae: bud scales +; sieve tube plastids also with proteinaceous fibrils; outer not inner A staminodial, style short.

Chemistry, Morphology, etc. Doweld (2001b) emphasized the similarities between Atherospermataceae and Gomortegaceae, especially the tracheoidal endotesta. Both have fruits in which the seed coat would be expected to have lost its protective function.

GOMORTEGACEAE Reiche   Back to Laurales

Alkaloids?; primary stem with separate bundles; nodes 1:2; secondary phloem with flaring rays; cuticle wax?; lamina entire; flower parts between spiral and whorled, hypanthium 0; P 5-7(-9), A 7-13, filaments rather slender, microsporogenesis modified simultaneous; G [2-3(-5)], inferior, archesporium single-celled, ovule apical, hemianatropous [or straight?], apotropous, stigmatic branches erect; fruit drupaceous; seed single, pachychalazal; embryo large; n = 21.

1/1: Gomortega keule. C. Chile, rare (map: from Donoso Z. 1994). [Photo - Flower]

• Gomortegaceae are aromatic plants with opposite, estipulate, entire leaves. The flowers are small, with staminodes outside the stamens, the ovary is inferior and syncarpous, and the single-seeded fruit is drupaceous.

Chemistry, Morphology, etc. Stern (1955) thought that nodal anatomy was unclear; here I follow Howard (in Metcalfe & Chalk 1987). The inflorescences, often described as being racemose, have a terminal flower. Vessel elements in young wood may have simple perforation plates (Metcalfe & Chalk 1987). Notice that although the body of the ovule is straight, its insertion on the funicle is oblique (cf. Endress & Igersheim 1997).

Some information is taken from Kubitzki (1993b: general), Doweld (2001: seed) and Heo et al. (2004: embryology).

ATHEROSPERMATACEAE R. Brown   Back to Laurales

(Hairs T-shaped); nodes 1:1; primary stem?; stomata anomocytic; leaves involute [Laurelia] or conduplicate; inflorescence racemose; T = K + C, tapetum plasmodial, pollen polar di- or meridionally syncolpate, reticulate; G 4-many, occluded by secretion as well, (archesporium single-celled), (stylulus none); fruit achenial, plumose, hypanthium woody; embryo also medium; n = 22, 57.

6-7[list]/16. New Guinea to New Zealand and New Caledonia, Chile, scattered (map: Renner et al.; Andrew Ford, pers. comm. [Australia]). [Photo - Fruit]

• Atherospermataceae have opposite, coarsely serrate leaves in which the lateral veins join to form a looping vein inside the margin. The flowers are quite small, the hypanthium is dry, and the individual fruitlets are plumose and achenial.

Evolution. The family is known from forests on the Antarctic Peninsula of the late Cretaceous/early Tertiary, with wood recorded from the Upper Eocene of Germany; the oldest fossils are ca 88 million years ago. An age for the clade as a whole of ca 140 million years has been suggested (Renner et al. 2000).

Chemistry, Morphology, etc. The plants do not accumulate aluminium (Webb 1954). Atherosperma has two sepals completely enclosing the bud, and then eight petals. The vasculature of the anther glands is independent of that of the anthers (Canright 1952).

Some information is taken from Philipson (1993); for wood anatomy (and that of Monimiaceae) see Poole and Gottwald (2001).

Phylogeny. Renner et al. (2000) suggest that a clade made up of Doryphora and Daphnandra, from the Queensland-New South Wales area of Australia, is sister to the rest of the family.

Monimiaceae [Hernandiaceae + Lauraceae]: (plants Al accumulators); (cork cambium outer cortical); crystals +, small; A whorled, columellae foot layer and endexine 0, ovule apical, (micropyle bistomal).

Chemistry, Morphology, etc. See Kimoto and Tobe (2008a) for a comprehensive summary of the variation in embryology and seed of the whole group.

MONIMIACEAE Jussieu   Back to Laurales

Also shrubs or lianes; (plants Al accumulators); primary stem with cylinder or separate bundles; (vessel elements with simple perforation plates); wood with broad rays; nodes 1:1-7; secondary phloem often with flaring rays; sieve tubes with rosette-like non-dispersive protein bodies; (sieve tube plastids also with filaments; starch alone); cuticle wax?; (stomata anomocytic); leaves conduplicate, (margins entire); plants monoecious or dioecious, (flowers perfect - Hortonia); flowers medium-sized, (hypanthium closed by roof); P 3-many, sepaloid, petaloid or calyptrate, (spiral); A 8-many, paired nectaries 0 (+ - Hortonia, Peumus, Mollinedia; filaments rather slender; connective produced; staminodes + - Hortonia, Peumus), anthers tetrasporangiate, dehiscing longitudinally, (tranversely bisporangiate - Monimia; dehiscence annular), tapetum secretory [Peumus]; G (1-few)-many, occluded by secretion as well, stylulus short (long - Palmeria), stigma stout, dry; fruit drupelets, (with fleshy appendages), hypanthium fleshy (splitting) or not; mesotesta usu. tracheidal, (endotesta not tracheidal); embryo short to quite long; n = (18-)19(-22, 39, 43, 57, etc.).

22[list]/200: Mollinedia (90 [?20 - S. Renner, pers. comm.]), Tambourissa (45), Kibara (45). Tropical, but esp. Australasia; fossil wood from the Campanian in Antarctica (map: S. Renner). [Photo: Fruit, Flower, Fruit, Levieria fruit, Wilkiea fruit].

• Monimiaceae are recognisable by their opposite, rather distantly serrate leaves which have prominent venation on the lower surface with the veins looping and joining near the margin, and their twigs, which have broad rays and are often flattened below the somewhat swollen nodes; some taxa have "laticiferous threads" (Keller 1996). In fruit, the well-developed fleshy hypanthium and/or receptacle is conspicuous; this may enclose the drupelets and it then splits irregularly.

Evolution. A hyperstigma may be present. The drupelets are surrounded by a fleshy, accrescent hypanthium. This may split, as in Palmeria, and the colour of the inside forms a striking contrast with that of the drupelets.

Chemistry, Morphology, etc. The pollen of Hortonia is remarkable: it has hollow, spiral sexinous strands and the intine is thick, with tangential channels. Decaryodendron has flowers with up to 1000 carpels, and flowers of Tambourissa have up to 2000 carpels; Mollinedia has carpels that are initially unsealed, but are later occluded by secretion. Kibaropsis has four cotyledons.

Phylogeny. Palmeria, Peumus, and Monimia together form a clade that is sister to the rest of the family (Renner 2002 and references). Fruit anatomy correlates quite well with phylogeny, e.g., the first three genera have a massively thick endocarp, alone in the family (Romanov et al. 2007).

Previous Relationships. As circumscribed here, Monimiaceae includes only Monimioideae, Hortonioideae and Mollinedioideae of Monimiaceae as circumscribed by Money et al. (1950), Cronquist (1981), and Takhtajan (1997); for the rest of the family, see Siparunaceae and Atherospermataceae.

Synonymy: Hortoniaceae A. C. Smith

Hernandiaceae + Lauraceae: primary stem ± with vascular cylinder; vessel elements with simple perforation plates; mucilage cells +; sieve tube plastids also with starch; hippocrepiform cells in pericycle?; leaves spiral, entire (lobed); flower parts whorled, (filaments slender), tapetum amoeboid, exine thin, spines set in a reduced granular layer, intine very thick, outre layer with a radially oriented micropfibrillar structure; G 1 [thus no extragynoecial compitum], ovule pachychalazal, outer integument ³4 cells across, (micropyle not covered), embryo sac more or less linear, hypostase 0, stigma dry; testa thick, multiplicative; endosperm 0; germination epigeal.

Evolution. The fossil Mauldinia may belong somewhere here, rather than within Lauraceae (Doyle & Endress 2007). Bandulskaia, from the Early Eocene of Tasmania and identified as Lauraceae based on several distinctive epidermal features, has huge leaf teeth 2000+ µm long that lack the glandular cap of teeth of other Laurales; independent origin of these teeth is likely (Carpenter et al. 2007).

Rohwer (2009) compares the heterodichogamous flowers of Lauraceae with those of Hernandiaceae and suggests that heterodichogamy may be common to the two; he interprets the floral morphology of Hernandiaceae in the context of this idea - heterodichogamy may thus be a synapomorphy at this level. For heterodichogamy in Hernandia, see Endress and Lorence (2004), and for additional possible synapomorphies, see Doyle and Endress (2000). Another scenario for ovary evolution is that it became inferior in the common ancester of Hernandiaceae and Lauraceae, persisting in the latter family in in Hyphodaphnis but subsequently becoming lost - both require two steps (two gains, versus gain and subsequent loss).

Chemistry, Morphology, etc. For the distinctive pollen of these two families, see Kubitzki (1981).

HERNANDIACEAE Berchtold & J. Presl   Back to Laurales

Trees or lianes; hippocrepiform sclereids in pericycle?; nodes 1:3-9; petiole bundles horizontally [Valvanthera] or vertically elliptic; (stomata anomocytic); branching from previous flush; leaf venation ± palmate; breeding system very variable; flowers (3-)4-5-merous; P 3-10; A 3-5(-7), (nectaries outside A, or 0, or highly reduced), ovary inferior, usu. facing abaxially, micropyle variable, outer integument 9-23 cells across, inner integument 3-8 cells across, stigma peltate; (fruit a samara).

5[list]/55 - two subfamilies below. Pantropical.

1. Hernandioideae

Al accumulation?; glandular hairs in leaf epidermis; inflorescence thyrsoid; anther valves laterally hinged, tapetal cells radially elongated, single layer of microspore mother cells, pollen grains 90-160 µm across, nucellus massive, 6-8 layers of parietal cells, nucellar beak +; bracteoles accrescent in fruit [not Illigera]; (seeds ruminate - usu. Hernandia), testa vascularised, spongy, tanniniferous, walls unthickened, mesotesta massive, 7-17 cells across; n = 18, 20.

3/44. Tropical, esp. Madagascar and Indo-Malesia (map: from Kubitzki 1969; van Balgooy 1975). [Photo - Hernandia Flower, Fruit, Illigera Flower, Fruit.]

Synonymy: Illigeraceae Blume

2. Gyrocarpoideae Pax

Leaves with cystoliths, strong higher-order vein areolation; inflorescence dichasial, ebracteate; flowers very small, P uniseriate, pollen grains 19-45 µm across, nucellar cap +, apical part of embryo sac protruding; cotyledons contortuplicate [much folded!]; n = 15.

2/10. Pantropical, esp. America (map: Kubitzki 1969; van Balgooy 1975).

Synonymy: Gyrocarpaceae Dumortier

• Given the variation in life form and vegetative and fruit morphology in Hernandiaceae, this is not an easy family to recognise. Illigera (Hernandioideae) is a climber with palmately compound leaves and sensitive petioles that can even be mistaken for the monocot Dioscorea, Sparattanthelium (Gyrocarpoideae)is a climber with recurved stem hooks, while Hernandia itself is a tree.

Chemistry, Morphology, etc. For floral morphology in Hernandia, see Endress and Lorence (2004); see Heo and Tobe (1995) for embryology, etc., and Kimoto and Tobe (2008) for more embryology and nice summary. Some information is also taken from Kubitzki (1969, 1993b).

LAURACEAE Jussieu   Back to Laurales

Flavones, 5-O-methyl flavonols, polyketides [acetogenins], (tryptamine alkaloids) +; (cork pericyclic - Cinnamomum; vessel elements with scalariform perforation plates; wood often fluorescing; (secondary phloem stratified); nodes 1:2 (1:3); also crystals and crystal sand +; (stomata anomocytic); bud scales + (0); branching from current flush; leaves (opposite), conduplicate or supervolute, often glaucous below, strong higher-order vein areolation; plants heterodichogamous (polygamous to dioecious), inflorescence umbellate to thyrsoid; (flowers 2-merous - Potameia), hypanthium often short, T 3 + 3 (2 + 2; K + C); A 3 [introrse] + 3 [often introrse] + 3 [extrorse; with glands] 1 whorl staminodial (4-several whorls of stamens; when dioecious, 3 whorls of staminodes in male plants, the third whorl of stamens=staminodes in female plants), sporangia widely separated, microspore mother cells in single row, (microsporogenesis simultaneous), (pollen monosulcate), outer integument 4-11 cells across, archesporium usu. unicellular, (stylulus 0), stigma also capitate; fruit also a berry, pedicels (and tepals) often thickened and colored; (seed ruminate), testa vascularised or not, endotestal cells longitudinally or transversely elongated; endosperm nuclear; n = (11-)12 (15 - Eusideroxylon, Endiandra), chromosomes 1-5(-7 - Cassytha) µm long.

1. Hypodaphnis

Anthers tetrasporangiate; glandular tapetum?; staminodes 0; G inferior.

1/1: Hypodaphnis zenkeri. Tropical West Africa.

Beilschmiedia, Cryptocarya, Endiandra, etc. [Cassytha [Caryodaphnopsis and Neocinnamomum + The Rest]]: subsidiary cells of paracytic stomata envelop the guard cell above and below, the latter having outer and inner cuticular ledges; staminodes +, glandular tapetum +, ovary superior, embryo sacs protruding from nucellus.

2. Beilschmiedia, Cryptocarya, Endiandra, etc.: ?

Stamens in two whorls (with three whorls, many).

6/710: Cryptocarya (350), Beilschmiedia (250), Endiandra (80). Pantropical, some subtropical, to New Zealand.

Cassytha [Caryodaphnopsis and Neocinnamomum + The Rest]

3. Cassytha

Parasitic herb; micropyle bistomal, nucellar cap 0; endosperm cellular.

1/16. Tropics, warm temperate in Australia - see The Parasitic Plant Collection.

Synonymy: Cassythaceae Lindley

Caryodaphnopsis and Neocinnamomum + The Rest: ?

Caryodaphnopsis + Neocinnamomum

Anthers tetrasporangiate.

2/21. Central and South America, South East Asia to the Philippines and Borneo.

5. The Rest

(Plant deciduous); tapetum amoeboid, (paired nectaries/glands 0 - Mezilaurus clade), embryo sac not protruding.

Ca 40/1730: Ocotea (350), Litsea (?400), Persea (200), Cinnamomum (350: cinnamon), Lindera (100). Pantropical (temperate).

Synonymy: Perseaceae Horaninow

• The family may be recognised by its aromatic smell, nearly always entire spiral or opposite (very rarely indeed two-ranked) leaves the blades of which are often quite thick (they are coriaceous when dry) and with a glaucous undersurface and rather steeply ascending secondary veins. The twigs are often more or less ridged, and branching is often on the current flush - even in temperate taxa there is often a mixture of proleptic and sylleptic branching on the same plant. The flowers are small, trimerous, and have valvate anthers; the fruit has a single, large seed that lacks endosperm and the pedicel - and sometimes also tepals and hypanthium - is often ± swollen and conspicuous. Some Lauraceae have a growth pattern similar to that of Myristicaceae, with whorled branches and periodic growth, but the leaves on the branches of Lauraceae are usually spiral, rarely opposite, while in Myristicaceae (and Annonaceae) the leaves are nearly always distichous.

Evolution. Lauraceae are prominent in Mid to Late Cretaceous floras, and include the Early Cenomanian Mauldinia which is ca 100 million years old (Drinnan et al. 1990; Viehofen et al. 2008). Mauldinia has remarkable inflorescences in which the lateral units are flattened and bilobed, bearing sessile flowers on their adaxial surfaces; these flowers are very like those of extant members of the family (see also Crepet et al. 2004; Friis et al. 2006b for references). The distichous bracts/prophylls of these inflorescence units is a distinctly odd feature in the family. Recently a flower provisionally assigned to Lauraceae, although with a unusual combination of floral characters - there are only two whorls of stamens and no nectaries/glands - has been described from deposits in Virginia some 112-105 million years old (von Balthazar et al. 2007). Chanderbali et al. (2001) suggest an age of 174 ± 32 million years before present for the family. Diversification in the speciose Ocotea is likely to have been rather recent (Renner 2005a).

Biogeographic relatips will depend on a more complete phylogeny, but it is interesting that the Macaronesia Persea indica is part of a New World clade - and sister (rather poor support) to this clade is another Macaronesian member of the family, Apollonias barbujana (Rohwer et al. 2009).

The family is prominent in the lowland tropical rainforests of South East Asia-Malesia and America in particular, and in tropical montane forests in the latter it may be the most speciose family (Gentry 1988).

The basic mode of flowering in the family may be heterodichogamy or dianthesis. Plants are of two types, and one plant will be in the staminate phase while the other is in the carpellate phase, and vice versa. The staminodes produce nectar when the plant/flower is in the carpellate phase and the staminal glands of the third staminal whorl produce nectar when the plant/flower is in the staminate phase (Rohwer 2009, see also above). Dispersal of the fruits is by animals.

Chemistry, Morphology, etc. Lindera, at least, has distinctive C₁₀, C₁₂ and C₁₄ monounsaturated fatty acids in its seeds (Badami & Patil 1981). Vestured pits are apparently absent; rays alone may be storied (Metcalfe 1987: P. van Rijckevorsel clarified reports of vestured pits and wood storying in the family). The distinctive paracytic stomata in which the subsidiary cell envelops the guard cell above and below, the latter having outer and inner cuticular ledges, may be an apomorphy for all Lauraceae except Hyphodaphnis (Carpenter et al. 2007), however, Nishida and van der Werff (2007) found more conventional stomata in at least some Lauraceae other than Mezilaurus. It has been suggested, largely on the basis of gene expression, that the perianth in some Lauraceae - Persea, at least - may represent modified stamens (Chanderbali et al. 2004, 2006). Both the tepals and the stamens of Persea have three traces (Reece 1939: the ovule is reported to be anatropous!). However, other reports suggest that the stamens have single traces, even if both whorls of tepals have three traces (Laurus) or often one trace in the inner whorl alone (Umbellularia - see Kasapligil 1951). Clearly more work is needed here. Multistaminate Lauraceae attain this condition by the increase in number of the stamen whorls. Dahlgrenodendron has pollen grains with exine, columellae, etc. Kimoto et al. (2006) summarize embryological findings in Lauraceae. Variation in the anatomy of the pericarp, development of the cupule in fruit, etc., is summarized by Little et al. (2009). The testa is not always multiplicative. Kasapligil (1951) described a tracheidal endotegmen at the radicular end of the seed. Both isozyme duplication and stomatal size increase over time suggest ancient polyploidy in this clade (Soltis & Soltis 1990; Masterson 1994). Is the base chromosome number 6?

Kimoto et al. (2006) note that a minor change on the tree that they used would mean that a glandular anther tapetum and possibly also protruding embryo sac arose on a single clade and did not reverse; they thought that characters like a glandular tapetum and an embryo sac protruding from the nucellus arose in parallel. However, in the topology suggested by Rohwer and Rudolph (2005: not cited by Kimoto et al. 2006) it appears that these characters are found in all (glandular tapetum) or most (protruding embryo sacs) members that have been examined on three successive branches of the tree, but are not, or only very rarely, found in the Mezilaurus group and other core Lauraceae. This suggests that there may have been reversal/loss of these characters in other Lauraceae; note that protruding embryo sacs are also found in Hernandiaceae-Gyrocarpoideae. I have optimised these and some other characters (especially von Balthazar et al. 2007) in the context of a provisional phylogeny of Lauraceae suggested by Rohwer and Rudolph (2005: see below), but it will be clear that where most of characters might properly be placed on the tree is very uncertain, both because the topology is uncertain and because our basic understanding of the morphological variation is poor.

General information is taken from Rohwer (1993a), some embryological details from Heo et al. (1998) and Endress and Sampson (1983), wood anatomy from Richter (1981) and van Rijckevorsel (2002), cuticle from Christophel et al. (1996), cytology from Oginuma et al. (1998), chromosome size from de Moraes et al. (2007), and androecial development from Buzgo et al. (2007).

Phylogeny. Hypodaphnis, with an inferior ovary, is sister to the rest of the family, then Cassytha (but a long branch), then Beilschmeidia + Cryptocarya + Endiandra, then Caryodaphnopsis, then Chlorocardium + Mezilaurus + Williamodendron (Rohwer 2000: matK); for more details, see Chanderbali et al. (2001). There are a number of taxa with long branches, and complex analyses by Rohwer and Rudolph (2005) strongly suggests a slight modification of this set of relationships: Hypodaphnis [[the Cryptocarya group] [Cassytha [[Caryodaphnopsis + Neocinnamomum] [[the Mezilaurus group] [core Lauraceae]]]]] - most of these clades have about 100% posterior probabilities. If this topology is confirmed, it will have considerable implications for character evolution (see above).

Litsea is polyphyletic, although section Litsea is monophyletic, and Lindera is also polyphyletic (Fijridiyanto & Murakami 2009). Note that the recognition of Neolitsea appears to make Actinodaphne paraphyletic (Li et al. 2007), results confirmed in a broader study (Li et al. 2008). For relationships in the Persea area, see Rohwer et al. (2009); Phoebe and Persea are para/polyphyletic, while the relationships of the Macaronesian Persea indica and perhaps Apollonias barbujana are with New World clades.

Classification. The genera are very difficult to recognise without flowers and are rather unsatisfactory even with them, often being based on single character differences in the androecium, such as sporangium number and direction of sporangium opening. However, both extrorse and introrse anthers can occur in the same flower, although the extrorse condition seems to be developmentally derived (Buzgo et al. 2007), thecae may be 2 or 4, their arrangement on the broad connective varies, etc. (e.g. Kopp 1966; Rohwer et al. 1991; Rohwer 1993, 1994a; van der Werff & Richter 1997); substantial changes in generic limits are to be expected.