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; shoot apical meristem complex; arbuscular mycorrhizae +; stem with ectophloic eustele, endodermis 0, xylem endarch; 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 ?; leaf vascular bundles collateral; leaves spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores] +, mono[ana]sulcate, pollen exine and intine homogeneous, ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development endo/exosporic, gametes two, with cell walls; 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, 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, numbers unstable, P not differentiated, outer members not enclosing the rest of the bud, A many, development centripetal, 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, pollen subspherical, binucleate at dispersal, trinucleate eventually, tectum continuous, endexine compact, lamellate only in the apertural regions, pollen tube elongated, with callose plugs, penetrating between cells, growth rate moderate, siphonogamy occuring, nectary 0, G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, micropyle endostomal, integuments 2-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte ?type, stylulus short, 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; pollen tectate-columellate, tectum reticulate [perforated]; 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.

LAURALES Perleb  Main Tree, Synapomorphies.

(Cork subepidermal); sieve tube plastids with protein crystalloids; nodes 1:?; petiole bundle(s) arcuate; leaves opposite; inflorescence ± cymose; hypanthium +, inner staminodia +, pollen ?, 1(-2) basal ovules/carpel, archesporium multicellular, stylulus long; 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.

Soltis et al. (2005b) summarise information on possible synapomorphies for the clade. Isorhamnetin occurs in Lauraceae, Gomortegaceae and "Monimiaceae" (Crawford et al. 1986). Little is known of obturator presence in the order, and of many other embryological details. Oginuma and Tobe (2006) suggest that the chromosome base number for the order is x = 11.

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 2005 for the most recent study).

See also Metcalfe (1987) for anatomy, Endress and Igersheim (1997) and Eklund (1999) for general information, Renner et al. (1997), Renner (1998, 1999) and Renner and Chanderbali (2000) for relationships, Kimoto and Tobe (2001) for embryology, and Renner (2005) for information on diversification. I am grateful to S. Renner for comments.

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

Synonymy: Calycanthales C. Martius, Gyrocarpales Dumortier, 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 perforations; 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, (anthers valvate - Sinocalycanthus), 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; Hong 1993; Fl. N. Am. III 1997; Qian & Ricklefs 2004). [Photo - Fruit © Robert Kowal] [Photo - Flower]

1. Idiospermum

Flavonols 0, but luteolin, etc. + [Crawford et al. 1986]; (vessel elements with scalariform perforations); P 10<, filaments flattened, G 1-2(-5), outer integument 12-15 cells thick, nucellar beak +, stigma fleshy, sessile; cotyledons (3-)4, massive, peltate.

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

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

2. The Rest.

P <10, A 5-18, filaments rather slender, pollen equatorially and vertically disulcate, G 5-many, outer integument 5-6(-8) cells thick, stigma filiform; 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]

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. It has anasulcate pollen like Idiospermum, which 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 (it may be sister to all other Laurales) or even Laurales is unclear (Eklund 1999; Crepet et al. 2005; Zhou et al. 2006; Doyle & Endress 2007). The rather younger (Turonian, ca 90 million years before present) Jerseyanthus 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 members of the tepals. Finally, isozyme duplication in Calycanthus may suggest that this clade shows ancient polyploidy (Soltis & Soltis 1990).

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 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.

For general information, see Nicely (1965) and Kubitzki (1993b), for the chloroplast genome, etc., see Goremykin et al. (2003b), for phylogeny and morphology, see Li et al. (2004), and for gynoecial development, see Staedler et al. (2007b).

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

[Siparunaceae [Atherospermataceae + Gomortegaceae]] [Monimiaceae + Hernandiaceae + Lauraceae]: evergreen trees; vessel elements with scalariform perforations; 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; (fruit with fleshy hypanthium/receptacle).

There is little information on tapetal development, or of most other embryological details and of seed anatomy; this is especially true of the first three families (see Kimoto & Tobe 2001 for a summary; Bello et al. 2002a for Siparuna). Leitão et al. (1999) summarize alkaloid distribution in Monimiaceae in the old sense (Atherospermataceae, Hernandiaceae, Monimiaceae s. str., Siparunaceae). See Doyle (2007) for monimioid teeth in this clade.

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

SIPARUNACEAE (A.-L. de Candolle) Schodde   Back to Laurales

Also lianes; plants Al accumulators; indumentum often stellate; vessel elements also with simple perforations; 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), stylodium 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.

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? Pollination is by gall midges. The fleshy appendage often differs in color from the rest of the fruit (see also Monimiaceae); it is called an aril by Renner and Hausner (1997) and occurs only in dioecious taxa. Dioecy seems to have evolved several times from monoecy in Siparunaceae (Renner & Won 2001).

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).

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

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, 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.

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 perforations (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 or not; 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), (style 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.

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 my has been suggseted (Renner et al. 2000).

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.

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). The apex of the ovule is exposed, as may also occur in Siparunaceae and Calycanthaceae (Endress & Igersheim 1997).

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

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

See Kimoto and Tobe (2008) 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 perforations); 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, style also short, stigma dry; fruit drupelets (with fleshy appendages), hypanthium fleshy (splitting) or not; (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.

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, those of Tambourissa have up to 2000 carpels; Mollinedia has carpels that are initially unsealed, but are later occluded by secretion. When the hypanthium splits, as in Palmeria, the colour of the inside of the hypanthium forms a striking contrast with that that of the drupelets. Kibaropsis has four cotyledons. A hyperstigma may be developed.

Palmeria, Peumus, and Monimia 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).

As circumscribed here, Monimiaceae includes Monimioideae, Hortonioideae and Mollinedioideae of Money et al. (1950) and Takhtajan (1997).

For information on this and other families previously included in it, i.e. Atherospermataceae and Siparunaceae, see Schodde (1970), Philipson (1993), Sampson (1993, 1997, 2007) and Foreman and Sampsonpollen), Renner (1998: phylogeny) and Romanov et al. (2007: fruit anatomy).

Synonymy: Hortoniaceae (J. R. Perkins & Gilg) A. C. Smith

Hernandiaceae + Lauraceae: primary stem ± with vascular cylinder; vessel elements with simple perforations; mucilage cells +; sieve tube plastids also with starch; leaves spiral, entire (lobed); flower parts whorled, (filaments slender), tapetum amoeboid, exine thin, intine very thick, G 1, ovule pachychalazal, outer integument 4< cells across, (micropyle not covered), embryo sac more or less linear, hypostase 0, stigma dry; testa thick; endosperm 0.

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 teeth 2000+ µm long that lack the glandular cap of teeth of other Laurales; independent origin is likely (Carpenter et al. 2007).

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), G inferior, usu. facing abaxially, micropyle variable, outer integument 9-23 cells across, inner integument 3-8 cells across, stigma peltate; (fruit a samara); testa multiplicative.

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, outer integument 10-23 cells thick, 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 - Flower] [Photo - Fruit]

Illigera is a climber with palmately compound leaves and sensitive petioles. [Photo - Flower] [Photo - 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).

Sparattanthelium is a climber with recurved stem hooks.

Synonymy: Gyrocarpaceae Dumortier

Given the variation in life form and basic vegetative morphology in Hernandiaceae, this is not an easy family to recognise; Illigera can even be mistaken for the monocot Dioscorea.

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

Trees (deciduous; herbaceous parasites); flavones, 5-O-methyl flavonols, polyketides [acetogenins], (tryptamine alkaloids) +; (cork pericyclic - Cinnamomum; vessel elements with scalariform perforations; 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; (plant 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] (1-3 whorls staminodial; stamens with four whorls-many), sporangia widely separated, (tapetum glandular), microspore mother cells in single row, (microsporogenesis simultaneous), (pollen monosulcate), G (inferior), outer integument 4-11 cells across, archesporium usu. unicellular, (style 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 - Eusideroxlon, Endiandra).

1. Hypodaphnis

Anthers tetrasporangiate, staminodes 0, G inferior.

1/1: Hypodaphnis. Tropical West Africa.

Beilschmeidia, 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 +, protruding embryo sacs.

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

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

6/710. 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. Old World tropics - see The Parasitic Plant Collection.

Synonymy: Cassythaceae Lindley

Caryodaphnopsis and Neocinnamomum + The Rest: ?

Caryodaphnopsis + Neocinnamomum

Anthers tetrasporangiate.

2/13. South East Asia to the Philippines and Borneo.

5. The Rest

Tapetum amoeboid, embryo sac not protruding.

Ca 40/1730. Pantropical (temperate).

Synonymy: Perseaceae Horaninow

• The family may be recognised by its aromatic smell, nearly always entire spiral or opposite (very rarely indeed 2-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.

Lauraceae are prominent in the Mid to Late Cretaceous flora, and include the Early Cenomanian Mauldinia (Drinnan et al. 1990), with its distinctive inflorescences yet flowers very like those of extant members of the family (see also Crepet et al. 2004; Friis et al. 2006b for references). Recently a flower provisionally assigned to Lauraceae, although with a distinctive combination of characters, 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.

The genera are very difficult and rather unsatisfactory, often being based on single character differences in the androecium (Rohwer 1993, 1994a; Werff & Richter 1997); 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 varies, etc.

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). 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: ovule 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 (Umbellularia - see Kasapligil 1951). Multistaminate Lauraceae attain this condition by the increase in number of the stamen whorls. Dahlgrenodendron has pollen grains with exine, columellae, etc. 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); x = 6?

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 below).

Kimoto et al. (2006) summarise embryological findings in Lauraceae. They note that a minor change on the tree that they use would mean that a glandular anther tapetum and possibly also protruding embryo sac arose on a single clade and did not reverse. 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 in core Lauraceae. This suggests that there may have been reversal/loss of these characters in other Lauraceae. Distinctive paracytic stomata in which the subsidiary cell envelops the guard cell above and below, the latter having outer and inner cuticular ledges, are an apomorphy for all Lauraceae except Hyphodaphnis (Carpenter et al. 2007, but cf. Nishida & van der Werff 2007 who found more conventional stomata in at least some other Lauraceae). I have optimised these and some other characters (see esp. von Balthazar et al. 2007) in the context of a provisional phylogeny of Lauraceae, but it will be clear that where most of characters might properly be placed on the tree is very uncertain.

General information is taken from Rohwer (1993a), some embryological details from Heo et al. (1998) and Endress and Sampson (1983), cytology from Oginuma et al. (1998), general wood anatomy from van Rijckevorsel (2002), and androecial development from Buzgo et al. (2007).