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.

CANELLALES + PIPERALES: flavonols, aporphine alkaloids +; nodes 3:3; G whorled.   Back to Main Tree

Doyle (2007) notes that the venation of members of this order is poorly differentiated and of low rank.

CANELLALES Cronquist  Main Tree, Synapomorphies.

Neolignans?, drimane-type sesquiterpenes +; indumentum 0; primary stem with continuous vascular cylinder; sieve tube plastids with starch and protein crystalloids and/or fibres; petiole bundle(s) arcuate; leaf cuticle waxes as tubules with nonacosan-10-ol the main wax; foliar sclereids +, branched; branching from previous innovation; flowers of moderate size, K and C distinct, micropyle bistomal; fruit a berry. - 2 families, 9-13 genera, 75-105 species.

Drimane-type sequiterpenoids are practically restricted to Canellales; they seem to be diverse in Canellaceae but are relatively uncommon in Winteraceae (Bastos et al. 1999).

For nodal anatomy, see Sugiyama (1979), for general vegetative anatomy, see Metcalfe (1987).

Includes Canellaceae, Winteraceae.

Synonymy: Winterales Reveal - Winteranae Doweld - Winteridae Doweld

CANELLACEAE Martius   Back to Canellales

Vessel elements with scalariform or reticulate perforations; true tracheids +; leaves spiral or 2-ranked; inflorescence variable; receptacular cortical vascular system +, K 3, C (4-)5-12, free (connate), A 6-12(-many), connate, (connective little produced), pollen (trichotomosulcate), ektexine also granular [Cinnamosma intectate], G [2-6], also occluded by secretion, placentation parietal, 2-many campylotropous ovules/carpel, micropyle zig-zag, style short, stigma lobed; fruit a berry, K persistent; seeds ruminate or not; exotesta sclerosed, rest undistinguished (?pachychalazal - Cinnamosma); endosperm development?; n = 11, 13, 14.

5[list]/13. Tropics; U.S.A. (S. Florida), Antilles, South America, E. Africa, Madagascar (Map: from Jackeline Salazar Lorenzo). [Photo - Flowers]

• Canellaceae are evergreen shrubs or trees often with rather pale bark that may be recognised by their rather thick, aromatic, exstipulate leaves with entire margins and flowers with three outer sepals, petals, connate stamens with extorse anthers, and ovary with parietal placentation. The fruit is a berry.

Are the sepals "really" bracts - perhaps unlikely? There has been discussion on the insertion of the petals, whether spiral or whorled, and if whorled, the number of whorls; Wilson (1966) also noted that the sepals have two traces and the petals three, although inner petals may have only a single trace. A vestigial aril has been reported from some genera (Igersheim & Endress 1997).

Some information is taken from Kubitzki (1993b); for chemistry, see Hegnauer 1964, 1989, 1990 - the last under Winteraceae), also Bastos et al. (1999: drimane-type sequiterpenoids).

WINTERACEAE Lindley   Back to Canellales

(Plant Al accumulator); vessels 0; rays 10+-seriate; (petiole bundles complex); hairs 0; leaves spiral, supervolute; inflorescence cymose (fasciculate); K 2-4(-6), connate and forming calyptra (calyptra splitting early), C (0-)2-many, (outer members connate), A spiral, 3-many, (subintrorse), filaments stout, (connective prolonged), pollen in acalymmate tetrads (monads), usu. monoporate or trichotomocolpate, semitectate-reticulate, (1-)5-many ovules/carpel, postgenital occlusion by complete fusion, nucellar cap +, hypostase +; stigma bilobed (not decurrent); K deciduous; seed with palisade exotesta, (endotegmen subfibrous).

4-7[list]/60-90. Montane tropics, not mainland Africa (Map: from Vink 1993). [Photo - Flower]

Taktajanioideae Leroy

Stomata anomocytic; G [2], placentation apical-parietal; fruit ?"septifragally" dehiscent; n = 18.

1/1. Takhtajania perrieri. Madagascar.

For the stomatal morphology of Takhtajania, see Baranova (2004a), for fruit anatomy, see Deroin (2000).

Synonymy: Taktajaniaceae (J.-F. Leroy) J.-F. Leroy

Winteroideae

Sesquiterpene dialdehyde cinnamates +; (vessel walls vestured); sieve elements with non-dispersive protein bodies; stomatal apertures often occluded by wax-cutin plugs; G (1-)5-many, fruit berrylet (follicle); n = 13, 43.

3-6/60-90. New Guinea to New Zealand and New Caledonia, few Borneo and the Philippines and South America, usu. not lowlands.

Sesquiterpene dialdehyde cinnamates are known only from this clade, and prenylated flananones have recently been found in Pseudowintera (Larsen et al. 2007).

• Winteraceae are often rather small evergreen trees or shrubs that can be recognised by their aromatic and/or peppery taste and their spiral, entire leaves that are often glaucous below. There is a more or less obviously calyptrate calyx more or less covering the flower although the other flower parts are nearly always free. The fruit is often a berrylet.

Fossils assigned to Winteraceae are have a much wider distribution than that of the family today (Vink 1993, for map). For records of fossil pollen, see Doyle (1999); such pollen is known from the Albian-Aptian some 125 million years before present. Fossil wood has been reported from the Maastrichtian of California (see Vink 1993, for literature). However, divergence of Takhtajania from other Winteraceae may have occured only some 46-41 million years ago (Wikström et al. 2001).

The occlusion of the stomatal apertures that is common in Winteroideae prevents these apartures from being wetted; Winteraceae in general grow in moist environments. The flowers of some Winteraceae show thermogenesis (Seymour 2001), and pollination is by a diversity of small insects, including thrips. In New Caledonia the primitive jawed moths, Sabatinca (Micropterigidae, sister to all other Lepidoptera), eat the pollen of Zygogynum; the tetrads are covered by much oily pollen-kitt which makes them stick to the moths. Sabatinca also uses the flowers as a place of assembly prior to mating (Thien et al. 1985: cf. Nothofagaceae). The flowers of some Winteraceae show thermogenesis (Seymour 2001).

Takhtajan (1997) suggests there are no alkaloids; Cronquist (1981) claims that there are at least some... Compression wood has been reported from Drimys (Westing 1965). The pericyclic sclerenchyma is of various origins (Metcalfe 1987). Deroin (2000) notes that there are no cortical bundles in the flower. Tasmannia is usually dioecious. Petals of Drimys s.l. have either one or three traces (see also Canellaceae!). The carpels of Tasmannia may be plicate.

The substitution rate of ITS rDNA seems to have been notably slow (Suh et al. 1993).

Is Drimys piperita the only species in Malesia, with Drimys also in S. America, or should there be two genera - Drimys (flowers perfect: South America) + Tasmannia (plant dioecious: 30+ species in New Guinea alone)? A generic distinction between the Old and New World taxa is strongly supported by Suh et al. (1993), Karol et al. (2000), Doust (2003) and Doust and Drinnan (2004), and there are clearly numerous (30+) species of Tasmannia in New Guinea and a few more at least in Borneo.

See also Hegnauer (1973, 1990: chemistry), Vink (1985, 1993: general), Svoma (1998b: ovules), Tobe and Sampson (2000: ovules), Ehrendorfer and Lambrou (2000: chromosome number), Keating (2000a: anatomy), and Sampson (2007: pollen) for further information.