EMBRYOPSIDA Pirani & Prado
Gametophyte dominant, independent, multicellular, initially ±globular; showing gravitropism; acquisition of phenylalanine lysase [PAL], phenylpropanoid metabolism [lignans +, flavonoids + (absorbtion of UV radiation)], xyloglucans in primary cell wall with distinctive side chains; plant poikilohydrous [protoplasm dessication tolerant], ectohydrous [free water outside plant physiologically important]; thalloid, leafy, with single-celled apical meristem, tissues little differentiated, rhizoids +, unicellular; chloroplasts several per cell, pyrenoids 0; glycolate metabolism in leaf peroxisomes [glyoxysomes]; centrioles/centrosomes in vegetative cells 0, microtubules with γ-tubulin along its length [?here], interphase microtubules form hoop-like system; metaphase spindle anastral, predictive preprophase band of microtubules [where cell plate will join parental cell wall], phragmoplast + [cell wall deposition spreading from around the spindle fibres], plasmodesmata +; antheridia and archegonia jacketed, surficial; blepharoplast +, centrioles develop de novo, bicentriole pair coaxial, separate at midpoint, centrioles rotate, associated with basal bodies of cilia, multilayered structure + [4 layers: L1, L4, tubules; L2, L3, short vertical lamellae] (0), spline + [tubules from L1 encircling spermatid], basal body 200-250 nm long, associated with amorphous electron-dense material, microtubules in basal end lacking symmetry, stellate array of filaments in transition zone extended, axonemal cap 0 [microtubules disorganized at apex of cilium]; male gametes [spermatozoids] with a left-handed coil, cilia 2, lateral; oogamy; sporophyte multicellular, cuticle +, plane of first cell division transverse [with respect to long axis of archegonium/embryo sac], sporangium and upper part of seta developing from epibasal cell [towards the archegonial neck, exoscopic], with at least transient apical cell [?level], initially surrounded by and dependent on gametophyte, placental transfer cells +, in both sporophyte and gametophyte, wall ingrowths develop early; suspensor/foot +, cells at foot tip somewhat haustorial; sporangium +, single, terminal, dehiscence longitudinal; meiosis sporic, monoplastidic, MTOC [MTOC = microtubule organizing centre] associated with plastid, sporocytes 4-lobed, cytokinesis simultaneous, preceding nuclear division, quadripolar microtubule system +; wall development both centripetal and centrifugal, sporopollenin + laid down in association with trilamellar layers [white-line centred lamellae; tripartite lamellae], >1000 spores/sporangium; nuclear genome size <1.4 pg, main telomere sequence motif TTTAGGG, LEAFY and KNOX1 and KNOX2 genes present, ethylene involved in cell elongation; chloroplast genome with close association between trnLUAA and trnFGAA genes, precursor for starch synthesis in plastid.
Many of the bolded characters in the characterization above are apomorphies of subsets of streptophytes along the lineage leading to the embryophytes, not apomorphies of crown-group embryophytes per se.
All groups below are crown groups, nearly all are extant. Characters mentioned are those of the immediate common ancestor of the group,  contains explanatory material, () features common in clade, exact status unclear.
Abscisic acid, L- and D-methionine distinguished metabolically; sporophyte with polar transport of auxins, class 1 KNOX genes expressed in sporangium alone; sporangium wall 4≤ cells across [≡ eusporangium], tapetum +, secreting sporopollenin, which obscures outer white-line centred lamellae, columella +, developing from endothecial cells; stomata +, on sporangium, anomocytic, cell lineage that produces them with symmetric divisions [perigenous]; underlying similarities in the development of conducting tissue and of rhizoids/root hairs; spores trilete; shoot meristem patterning gene families expressed; MIKC, MI*K*C* genes, post-transcriptional editing of chloroplast genes; gain of three group II mitochondrial introns, mitochondrial trnS(gcu) and trnN(guu) genes 0.
[Anthocerophyta + Polysporangiophyta]: xyloglucans in the primary cell wall with fucosylated subunits; gametophyte leafless; archegonia embedded/sunken [on;y neck protruding]; sporophyte long-lived, chlorophyllous; cell walls with xylans.
Sporophyte dominant, branched, branching apical, dichotomous, potentially indeterminate; vascular tissue +; stomata on stem; sporangia several, each opening independently; spore walls not multilamellate [?here].
EXTANT TRACHEOPHYTA / VASCULAR PLANTS
Sporophyte with photosynthetic red light response; (condensed or nonhydrolyzable tannins/proanthocyanidins +); plant homoiohydrous [water content of protoplasm relatively stable]; control of leaf hydration passive; plant endohydrous [physiologically important free water inside plant]; (condensed or nonhydrolyzable tannins/proanthocyanidins +); xylans in secondary walls of vascular and mechanical tissue; lignins +; stem apex multicellular, with cytohistochemical zonation, plasmodesmata formation based on cell lineage; tracheids +, in both protoxylem and metaxylem, G- and S-types; sieve cells + [nucleus degenerating]; endodermis +; leaves/sporophylls spirally arranged, blades with mean venation density ca 1.8 mm/mm2 [to 5 mm/mm2], all epidermal cells with chloroplasts; sporangia adaxial, columella 0; tapetum glandular; ?position of transfer cells; MTOCs not associated with plastids, basal body 350-550 nm long, stellate array in transition region initially joining microtubule triplets; suspensor +, shoot apex developing away from micropyle/archegonial neck [from hypobasal cell, endoscopic], root lateral with respect to the longitudinal axis of the embryo [plant homorhizic].[MONILOPHYTA + LIGNOPHYTA]
Sporophyte endomycorrhizal [with Glomeromycota]; growth ± monopodial, branching spiral; roots +, endogenous, positively geotropic, root hairs and root cap +, protoxylem exarch, lateral roots +, endogenous; G-type tracheids +, with scalariform-bordered pits; leaves with apical/marginal growth, venation development basipetal, growth determinate; sporangium dehiscence by a single longitudinal slit; cells polyplastidic, MTOCs diffuse, perinuclear, migratory; blepharoplasts +, paired, with electron-dense material, centrioles on periphery, male gametes multiciliate; chloroplast long single copy ca 30kb inversion [from psbM to ycf2]; LITTLE ZIPPER proteins.
Sporophyte woody; stem branching lateral, meristems axillary; lateral root origin from the pericycle; cork cambium + [producing cork abaxially], vascular cambium bifacial [producing phloem abaxially and xylem adaxially].
Plants heterosporous; megasporangium surrounded by cupule [i.e. = unitegmic ovule, cupule = integument]; pollen lands on ovule; megaspore germination endosporic [female gametophyte initially retained on the plant].
EXTANT SEED PLANTS / SPERMATOPHYTA
Plant 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 particularly with guaiacyl and p-hydroxyphenyl [G + H] units [sinapyl units uncommon, no Maüle reaction]; root stele with xylem and phloem originating on alternate radii, cork cambium deep seated; stem apical meristem complex [with quiescent centre, etc.], plasmodesma density in SAM 1.6-6.2[mean]/μm2 [interface-specific plasmodesmatal network]; eustele +, protoxylem endarch, endodermis 0; wood homoxylous, tracheids and rays alone, tracheid/tracheid pits circular, bordered; mature sieve tube/cell lacking functioning nucleus, sieve tube plastids with starch grains; phloem fibres +; cork cambium superficial; leaf nodes 1:1, a single trace leaving the vascular sympodium; leaf vascular bundles amphicribral; guard cells the only epidermal cells with chloroplasts, stomatal pore with active opening in response to leaf hydration, control by abscisic acid, metabolic regulation of water use efficiency, etc.; axillary buds +, exogenous; prophylls two, lateral; leaves with petiole and lamina, development basipetal, lamina simple; sporangia borne on sporophylls; spores not dormant; microsporophylls aggregated in indeterminate cones/strobili; grains monosulcate, aperture in ana- position [distal], primexine + [involved in exine pattern formation with deposition of sporopollenin from tapetum there], exine and intine homogeneous, exine alveolar/honeycomb; ovules with parietal tissue [= crassinucellate], megaspore tetrad linear, functional megaspore single, chalazal, sporopollenin 0; gametophyte ± wholly dependent on sporophyte, development initially endosporic [apical cell 0, rhizoids 0, etc.]; male gametophyte with tube developing from distal end of grain, male gametes two, developing after pollination, with cell walls; female gametophyte initially syncytial, walls then surrounding individual nuclei; embryo cellular ab initio, suspensor short-minute, embryonic axis straight [shoot and root at opposite ends; plant allorhizic], cotyledons 2; embryo ± dormant; ycf2 gene in inverted repeat, mitochondrial trans- nad2i542g2 and coxIIi3 introns present; whole nuclear genome duplication [ζ - zeta - duplication], two copies of LEAFY gene, PHY gene duplications [three - [BP [A/N + C/O]] - copies], 5.8S and 5S rDNA in separate clusters.
ANGIOSPERMAE / MAGNOLIOPHYTA
Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, apigenin and/or luteolin scattered, [cyanogenesis in ANA grade?], lignin also with syringyl units common [G + S lignin, positive Maüle reaction - syringyl:guaiacyl ratio more than 2-2.5:1], hemicelluloses as xyloglucans; root apical meristem intermediate-open; stele di- to pentarch [oligarch], pith relatively inconspicuous, 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, hypodermis suberised and with Casparian strip [= exodermis]; shoot apex with tunica-corpus construction, tunica 2-layered; starch grains simple; primary cell wall mostly with pectic polysaccharides, poor in mannans; tracheid:tracheid [end wall] plates with scalariform pitting, wood parenchyma +; sieve tubes enucleate, sieve plate with pores (0.1-)0.5-10< µm across, cytoplasm with P-proteins, not occluding pores of plate, companion cell and sieve tube from same mother cell; sugar transport in phloem passive; nodes 1:?; dark reversal Pfr → Pr; protoplasm dessication tolerant [plant poikilohydric]; stomata brachyparacytic [ends of subsidiary cells level with ends of pore], outer stomatal ledges producing vestibule, reduction in stomatal conductance with increasing CO2 concentration; lamina formed from the primordial leaf apex, margins toothed, development of venation acropetal, overall growth ± diffuse, secondary veins pinnate, fine venation hierarchical-reticulate, (1.7-)4.1(-5.7) mm/mm2, vein endings free; flowers perfect, pedicellate, ± haplomorphic, protogynous; parts free, numbers variable, development centripetal; P +, ?insertion, members each with a single trace, outer members not sharply differentiated from the others, not enclosing the floral bud; A many, filament not sharply distinguished from anther, stout, broad, with a single trace, anther introrse, tetrasporangiate, sporangia in two groups of two [dithecal], each theca dehiscing longitudinally by a common slit, ± embedded in the filament, walls with at least outer secondary parietal cells dividing, endothecium +, cells elongated at right angles to long axis of anther; tapetal cells binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, tectum continuous or microperforate, ektexine columellate, endexine lamellate only in the apertural regions, thin, compact, intine in apertural areas thick, pollenkitt +; nectary 0; carpels present, superior, free, several, ascidiate [postgenital occlusion by secretion], stylulus at most short [shorter than ovary], hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, carinal, dry, extragynoecial compitum +; ovules few [?1]/carpel, marginal, anatropous, bitegmic, micropyle endostomal, outer integument 2-3 cells across, often largely subdermal in origin, inner integument 2-3 cells across, often dermal in origin, parietal tissue 1-3 cells across, nucellar cap?; megasporocyte single, hypodermal, functional megaspore lacking cuticle; female gametophyte lacking chlorophyll, not photosynthesising, four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; ovule not increasing in size between pollination and fertilization; pollen grains land on stigma, bicellular at dispersal, mature male gametophyte tricellular, germinating in less than 3 hours, pollen tube elongated, unbranched, growing between cells, growth rate (20-)80-20,000 µm/hour, apex of pectins, wall with callose, lumen with callose plugs, penetration of ovules via micropyle [porogamous], whole process takes ca 18 hours, distance to first ovule 1.1-2.1 mm; male gametes lacking cell walls, ciliae 0, siphonogamy; double fertilization +, ovules aborting unless fertilized; P deciduous in fruit; mature seed much larger than fertilized ovule, small , dry [no sarcotesta], exotestal; endosperm +, cellular, development heteropolar [first division oblique, micropylar end initially with a single large cell, divisions uniseriate, chalazal cell smaller, divisions in several planes], copious, oily and/or proteinaceous, embryo short [<¼ length of seed]; plastid and mitochondrial transmission maternal; Arabidopsis-type telomeres [(TTTAGGG)n]; nuclear genome very small [1C = <1.4 pg, 1 pg = 109 base pairs], whole nuclear genome duplication [ε/epsilon event]; ndhB gene 21 codons enlarged at the 5' end, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, palaeo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and three copies of the PHY gene, [PHYB [PHYA + PHYC]]; chloroplast chlB, -L, -N, trnP-GGG genes 0.
[NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]]: wood fibres +; axial parenchyma diffuse or diffuse-in-aggregates; pollen monosulcate [anasulcate], tectum reticulate-perforate [here?]; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.
[AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]] : vessel elements with scalariform perforation plates in primary xylem; essential oils in specialized cells [lamina and P ± pellucid-punctate]; tension wood + [reaction wood: with gelatinous fibres, g-fibres, on adaxial side of branch/stem junction]; tectum reticulate; anther wall with outer secondary parietal cell layer dividing; nucellar cap + [character lost where in eudicots?]; 12BP [4 amino acids] deletion in P1 gene; PHYE +. Back to Main Tree
Age. Wikström et al. (2001) suggested an age of (172-)165, 147(-140) m.y. for this node, while ages in Bell et al. (2010: BEAST exponential and lognormal respectively) are (187-)173(-160) or (150-)144(-138) m.y.; Soltis et al. (2008) give dates of some 174-127 m.y., Moore et al. (2010) ages of (151-)144(-138) m.y., and Iles et al. (2014) ages of (145.6-)140.2(-135.5) m.y.a, while ca 137.7 m.y.a. is the age in Magallón et al. (2015). Magallón and Castillo (2009) offer very divergent estimates - ca 235.5 and 129.7 m.y. for relaxed and constrained penalized likelihood datings respectively. Clarke et al. (2011: q.v. for other estimates) suggest ages of (208-)177(-152) m.y., N. Zhang et al. (2012; Xue et al. 2012 are very similar) ages of (185-)161(-146) m.y., and Magallón et al. (2013) an age of around 170.4 m.y. ago. At (250, 215-)211, 180(-156) and ca 237 m.y.a, the estimates by Zeng et al. (2014) and Z. Wu et al. (2014) respectively are towards the upper end of the spectrum.
A fossil-based estimate for the age of this clade is ca 113 m.y. (Crepet et al. 2004).
Chemistry, Morphology, etc. See Hegnauer (1990) for a discussion of the chemistry of the Polycarpicae, which also includes the magnoliids and Ranunculales. The sampling for the presence/absence of tension wood is poor, for instance, only one member of Austrobaileyales is mentioned in Höster and Liese (1966), and its position at this node is only provisional. Cuticular striations are known to occur only at and above this node (Upchurch 2013).
Columellar infratectal structure of pollen grains may be best optimised here; the plesiomorphic condition is granular, also found in the pollen of several Magnoliales, Monimiaceae, etc., as reversals (Doyle et al. 1990b). For the 12BP deletion, see S. Kim et al. (2003, 2004b) and Aoki et al. (2004).
AUSTROBAILEYALES Reveal Main Tree.
Tiglic acid +; vessels solitary; nodes 1:2; petiole bundle(s) arcuate; lamina margin?; outer integument 5-7 cells thick; fruit a berrylet; P deciduous; mesotestal cells ± sclerotic; endosperm starchy, also proteins and lipids. - 3 families, 5 genera, 100 species.
Age. Tank et al. (2015: Table S2) thought that this node might be ca 179 m.y.o., Wikström et al. (2001) suggested an age of (155-)148, 133(-126) m.y. for crown Austrobaileyales, Schneider et al. (2004) ages of 168 and 85 m.y., Magallón and Castillo (2009) ages of ca 203 and 125 m.y., Bell et al. (2010) ages of (145-)122(-99) (see also Magallón et al. 2015) or (130-)114(-110) m.y., while Iles et al. (2014) suggested an age of (130.8-)118.3(-109.9) m.y. ago. Somewhat younger estimates include those by Magallón et al. (2013) who thought that this node might be some 103.4 m.y. old, while ca 91.5 m.y. is the estimate in Naumann et al. (2013).
Note: Boldface denotes possible apomorphies, (....) denotes a feature common in the clade, exact status uncertain, [....] includes explanatory material. Note that the particular node to which many characters, particularly the more cryptic ones, should be assigned is unclear. This is partly because homoplasy is very common, in addition, basic information for all too many characters is very incomplete, frequently coming from taxa well embedded in the clade of interest and so making the position of any putative apomorphy uncertain. Then there are the not-so-trivial issues of how character states are delimited and ancestral states are reconstructed (see above).
Evolution. Divergence & Distribution. Endress and Doyle (2015) discuss some apomorphies (floral morphology).
Ecology & Physiology. For the evolution of the liane habit, common here, in the context of plants with rather unspecialized vascular systems, see Feild and Isnard (2013) and Isnard and Feild (2015).
Pollination Biology & Seed Dispersal. Thien et al. (2009) survey what is known about pollination in the clade.
Chemistry, Morphology, etc. The wood has paratracheal parenchyma (Carlquist & Schneider 2001). Laterocytic stomata are common in the order, and the cuticle surface is radiate-striate around the secretory cells on the lower surface of the leaf blade in Austrobaileyaceae and Schisandraceae, at least (Baranova 2004b for discussion; Carpenter 2006).
For vegetative anatomy, see Metcalfe (1987), for some developmental morphology of ovules and seeds, inc. details of lobing, etc., at micropyle, see Yamada et al. (2003a). For embryo sac and endosperm development, see Floyd and Friedman (2001), Friedman et al. (2003), Williams and Friedman (2004) and Tobe et al. (2007).
Phylogeny. For the circumscription of the order, see Soltis et al. (1997) and Källersjö et al. (1999); Trimeniaceae are also to be included (e.g. Qiu et al. 1999). Austrobaileyaceae are sister to the other members of the order.
Includes Austrobaileyaceae, Schisandraceae, Trimeniaceae.
Synonymy: Illicineae J. Presl - Illiciales Cronquist, Schisandrales Martius, Trimeniales Doweld - Schisandrineae Shipunov - Austrobaileyanae Chase & Reveal, Illicianae Doweld, Trimenianae Doweld - Illiciidae C. Y. Wu
AUSTROBAILEYACEAE Croizat, nom. cons. Back to Austrobaileyales
Liane, climbing by twining; alkaloids 0, flavonols?; primary stem with separate bundles; wood with broad rays; sieve elements with non-dispersive protein bodies; calcium oxalate as crystal sand; (stomata anomocytic); leaves ± opposite, lamina vernation conduplicate, margins entire, petiole short; flowers axillary, large [ca 5 cm across], cortical vascular system?; P 12-24, with two traces; A 6-11, laminar, vascular bundle(s) branching, anthers embedded in connective, staminodes internal, 6 or more; G (4-)6-9(-14), stigma bilobed; ovules (4-)6-8(-14)/carpel, apotropous; seeds ruminate, perichalazal; testa multiplicative, vascularized, sarcotesta +, outer mesotesta lignified; n = 22, ?23; germination epigeal.
1[list]/2. Australia (map: from Heywood 1978). [Photo - Flower.]
Chemistry, Morphology, etc. There is some discussion as to whether the highly inclined end walls of the sieve tube have sieve plates, or not (Evert 2006: 393 for literature); in any event, other details of the sieve connections are typically angiosperm. The stylar canal is filled with secretion.
See Bailey and Swamy (1949) and Endress (1993) for general information, Carlquist (2001) for wood anatomy;, Behnke (1986) for phloem anatomy, pores are very narrow, Endress (1980a, 1984) for floral morphology, and Zavada (1984) for pollen (c.f. Furness 2014).
[Schisandraceae + Trimeniaceae]: flowers <3 cm across; pollen other than mono[ana]sulcate; infra-stylar extra-gynoecial compitum/pollen tube growth; stigma dry; megaspore mother cells 2-many; exotesta ± palisade.
Age. Ages for this node of (107.9-)102.1(-98.8.) m.y.a. (Iles et al. 2014), ca 109.7 m.y.a. (Magallón et al. 2015) or as much as around 158.6 m.y. (Tank et al. 2015: Table S2) have been suggested.
Anacostia, fossils with graded-reticulate monosulcate to trichotomosulcate pollen and exotestal seeds from Cretaceous (Barremian-Aptian) deposits some 130-115 m.y. old of E. North America and Portugal (Friis et al. 1997b), may be sister to Schisandraceae (Doyle & Endress 2010, 2014; Doyle & Upchurch 2014), not really compatible with the estimate in the preceding paragraph. However, Friis et al. (2011) found the fossils hard to place.
SCHISANDRACEAE Blume, nom. cons. Back to Austrobaileyales
Tetracyclic triterpenes [cycloartanes], flavonols +, flavones 0, tanniniferous; primary stem ± with vascular cylinder; (phoem fibres +); true tracheids +; astrosclereids +; mucilage cells +; (leaf epidermis silicified); lamina vernation supervolute; A 4-many, latrorse to introrse, pollen tricolpate, syncolpate pole distal, semitectate-reticulate, muri tall; stigma dry; exotesta with sinuous anticlinal cell walls, ?lignified mesotesta; n = 13, 14.
3/92. Sri Lanka and South East Asia to W. Malesia, S.E. U.S.A., E. Mexico, Greater Antilles.
Age. Magallón et al. (2013) suggested an age for crown-group Schisandraceae of around 42.2 m.y. and Naumann et al. (2013) an age of ca 40 m.y., and estimates are slightly under 50 m.y. in N. Zhang et al. (2012). Ages in Morris et al. (2007) are very different, the age being around 131.7 m.y., while those in Wikström et al. (2001) at (119-)108, 93(-82) m.y. are somewhat intermediate, as are those in Bell et al. (2010), at 91-89 m.y.. The latter two ages are likely to be underestimates if the identity of the trimeniaceous fossil seed (see below) is correct.
Shrubs or trees; plants Al accumulators; (pits vestured); nodes 1:1; branching on previous innovation; leaves pseudoverticillate, lamina margins entire; P (7-)12-many; G (5-)7-15(-21), pseudo-whorled, residual axis massive; occlusion also by postgenital fusion; ovule 1/carpel, near basal, parietal tissue ca 6 cells across; fruit an explosive follicle; seed with a circular cap; testa multiplicative; endosperm lacking starch, develops in chalazal half [?level].
1/42. South East Asia to W. Malesia, S.E. U.S.A., E. Mexico, Greater Antilles (map: from Wood 1972). [Photo - Flower, Fruit.]
Age. Morris et al. (2007) suggested that crown group Illicium was (91.5-)89.4, 76.3(-72.2) m.y. old.
Synonymy: Illiciaceae Berchtold & Presl nom. cons.
Schisandra Blume + Kadsura Jussieu
Lianes, climbing by twining; (silicon concentration high); distinctive neolignans, myricetin +; vessel elements with simple perforation plates; nodes 1:3; sclereids fibre-like, with crystals in the walls; stomata also laterocytic; leaves (two-ranked), lamina (vernation involute), teeth with clear persistent swollen cap into which proceed higher order veins as well as secondaries or tertiaries (margins entire); plant monoecious or dioecious; P 5-15, A 4-7, ± connate, endothecium biseriate; pollen heteropolar, (6 colpate); G 12-many, stigma papillate; ovules 2-5(-11)/carpel, parietal tissue 2-3 cells across, nucellar cap ca 2 cells across; (more than one embryo sac developing); berrylets usu. 2-seeded, receptacle enlarging greatly; endotesta also lignified; cotyledons convolute; n also = 7.
1-2[list]/50. Sri Lanka, East Asia to W. Malesia, S.E. U.S.A., Mexico (map: from Saunders 1998, 2000).[Photo - Infructescence.]
Synonymy: Kadsuraceae Radogizky
Evolution. Divergence & Distribution. For the fossil record of Illiciaceae, which dates back only to the Late Cretaceous, see Friis et al. (2011).
Z. Liu et al. (2006) discuss character evolution in Schizandra.
Pollination Biology & Seed Dispersal. Illicium, Schisandra glabra (Schisandra s. str.) and Kadsura longipedunculata all have thermogenic flowers (Seymour 2001; Liu et al. 2006; Yuan et al. 2008); pollen may be a floral reward for the pollinator, and/or deceit may be involved. Reports of nectar/nectaries need to be substantiated (Erbar 2014). For the growth of the pollen tube through mucilage on the surface of the epidermis rather than between cells, i.e. the presence of an extragynoecial compitum, and the nature of the stigma surface, see E. G. Williams et al. (1993), Lyew et al. (2007) and Du and Wang (2012).
Romanov et al. (2013) discuss the the explosive dehiscence of the follicle of Illicium and its distinctive anatomy.
Chemistry, Morphology, etc. The vessel member endings of Illicium may also be reticulate. The prophylls of Schizandra are reported to be adaxial (Keller 1996); those I have seen are lateral.
The anther connective is especially well developed. The pollen is modified monosulcate (via trichotomonosulcate). The endotegmen may persist (Corner 1977).
Some general information is taken from Bailey and Nast (1948), Keng (1993), and Saunders (1997, 2000), Sy et al. (1997) discuss phytochemical relationships, Floyd and Friedman (2001) outline endosperm development, while Swamy (1964a: embryo sac unlike any others he knew), Friedman et al. (2003a, esp. b) and Friedman and Williams (2004) provide information on the female gametophyte. For wood anatomy, see Yang and Lin (2007), for floral development, see Robertson and Tucker (1979), Tucker (1984), Tucker and Bourland (1994) and Dong et al. (2012), and for pollen morphology, see Wang et al. (2010).
Phylogeny. Kadsura may be paraphyletic, based on the analysis of both trnL-F and ITS sequences, although paraphyly is not found in morphological analyses (Hao et al. 2001; Denk & Oh 2006; Liu et al. 2006). Molecular and morphological studies also suggest rather different relationships within Illicium (Hao et al. 2000; Oh et al. 2003).
Classification. There is the option in A.P.G. II (2003) of placing the two parts of this quite well characterised clade in separate families, but combination seems in order (A.P.G. III 2009).
TRIMENIACEAE Gibbs, nom. cons. Back to Austrobaileyales
Trees or lianes; 5-O-methyl flavonols, flavones +, alkaloids?; primary stem with separate bundles; (vessels in radial multiples); rays 6-9-seriate; (secondary phloem with broad rays); mucilage cells +; leaves opposite, lamina margins entire or toothed; inflorescence axillary (terminal), branched; plants monoecious or flowers perfect; receptacle small; P 2-many, outer in pairs, otherwise spiral; A 6-25, anthers latrorse to extrorse (± introrse), connective somewhat prolonged; pollen disulcate, polyporate or inaperturate, monads or tetrads, endexine lamellate; G 1 (2), style 0, stigma ± penicillate, extragynoecial compitum 0; ovule 1/carpel, pendulous, micropyle bistomal, parietal tissue 9-30+ cells across, nucellar cap ca 6 cells across, hypostase +; megaspore mother cells at base of nucellus, embryo sac much elongated (few), reaching micropyle; seed with a circular cap; testa vascularized, almost all cell walls thick, outer layers lignified, palisade, (mesotesta not lignified); thin layer of nucellus persistent; n = 9.
1-2[list]/6. New Guinea and S.E. Australia to Fiji (map: from van Balgooy 1975; Philipson 1986b).
Age. Distinctive trimeniaceous seeds, albeit without the vascularized testa of extant taxa, have been found in Late Albian deposits some 118 m.y. old in Hokkaido, Japan (Yamada et al. 2008).
Evolution. Pollination Biology & Seed Dispersal. For pollination, see Bernhardt et al. (2003); stigmatic self-incompatibility occurs here, and both wind and insects may be involved in pollination.
Chemistry, Morphology, etc. Some plants of Trimenia papuana have inaperturate pollen, while some have polyporate pollen (Sampson 2007); the endexine is lamellate. The nucellus sometimes elongates greatly after meiosis of the megaspore mother cells, but the origin of the cells making up the massive nucellus and through the central, starch-rich cells of which the embryo sac grows (Bachelier & Friedman 2011; Friedman & Bachelier 2013) and of the megaspore mother cells themselves is unclear; are the latter initially hypodermal? Friedman and Bachelier (2013: much useful information) observed a thin, persistent layer of nucellar tissue surrounding the endosperm, but it did not contain food reserves.
See also Endress and Sampson (1983: floral development) and Philipson (1986b, 1993) for more information.