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.

PROTEALES [TROCHODENDRALES [BUXALES [GUNNERALES + CORE EUDICOTS]]]: ?

TROCHODENDRALES [BUXALES [GUNNERALES + CORE EUDICOTS]]: benzylisoquinoline alkaloids 0; euAP3 + TM6 genes [duplication of paleoAP3 gene: B class], mitochondrial rps2 gene lost.

BUXALES [GUNNERALES + CORE EUDICOTS]: ?

GUNNERALES + CORE EUDICOTS: Ellagic and gallic acids common, cyanogenesis via phenylalanine, isoleucine or valine pathways; micropyle?; PI-dB motif +, small deletion in the 18S ribosomal DNA common.

CORE EUDICOTS: Root apical meristem closed; flowers rather stereotyped: 5-merous, parts whorled, K and C distinct, K with 3 traces, A = 2x K, internal to the C whorl, (numerous, but then often fasciculate and/or centrifugal), pollen tricolporate, (nectary disc +), [G 5], [3] also common, compitum +, placentation axile, stigma not decurrent; endosperm nuclear; fruit dry, dehiscent, loculicidal [when a capsule]; euAP1 + euFUL + AGL79 genes [duplication of AP1/FUL or FUL-like gene], PLE + euAG [duplication of AG-like gene: C class], SEP1 + FBP6 genes [duplication of AGL2/3/4 gene].

Dilleniales + Caryophyllales: tension wood 0; successive cambia +; vessel elements with simple perforations; wood with SiO₂ bodies; nodes 3 or more:3 or more; leaves spiral; K persistent in fruit.   Back to Main Tree

See the Berberidopsidales page for discussion on the relationships of these two orders, which have no firm position as yet. Some evidence, including seed coat anatomy, suggests a relationship between Dilleniales and Vitales, but relationships between Dilleniales and Caryophyllales have also been suggested (e.g. D. Soltis et al. 2003a; Soltis et al. 2007a). Horne (2006) lists a number of features suggesting a relationship between Dilleniaceae and Rhabdodendraceae, probably sister to the rest of Caryophyllales, in particular; some of these are features (?synapomorphies?) of [Dilleniales + Caryophyllales], and the status of the others depends on an improved resolution of relationships.

DILLENIALES Hutchinson  Main Tree, Synapomorphies.

Secondary veins proceeding straight to the teeth; A many, often centrifugal, G separate, ?micropyle; fruit a follicle; endotesta ± palisade, lignified, exotegmen usu. tracheidal. - 1 family, 10 genera, 300 species.

Includes Dilleniaceae.

Synonymy: Dillenianae Takhtajan - Dilleniidae Reveal & Takhtajan

DILLENIACEAE Salisbury   Back to Dilleniales

Trees and shrubs (lianes, perennial herbs); distinctive flavonols, myricetin, ellagic acid +; hairs ± stellate [esp. Hibbertia] and sclerified; primary stem with continuous cylinder; (successive cambia +); cork deep-seated (superficial in Dillenia); (vessel elements with simple perforations); true tracheids +; (nodes 1:1 [Hibbertia]); raphides +, also common in wood; epidermis silicified; branching from previous flush; hairs unicellular; leaves spiral, conduplicate, often scabrid, margins toothed (entire), 2ndary veins parallel, teeth with clear glandular expanded apex, base rather broad, stipules 0, or long petiolar flanges [amplexicaul petiole]; inflorescence?; pedicels articulated, (flowers horizontally monosymmetrical); K (3-)5(-20), C (2-)5, often crumpled in bud, A often asymmetrical, (1-)many, from ring primordium or fasciculate, supplied by trunk bundles, (staminodes +), connective often well-developed, anthers basifixed, (dehiscing by pores), exodermis well developed, (pollen colpate), nectary 0, G (1-3)4-8[-20], opposite C, or odd member adaxial, 1-many (atropous) apotropous often campylotropous ovules/carpel, micropyle zigzag or exostomal, chalaza massive, stigmas capitate to punctate, wet (1 record); (fruit a nut; berry), (K enclosing fruit, ± fleshy); funicular aril, often laciniate, exotesta often fleshy (cells large, tanniniferous, becoming flattened - Dillenia), exotegmen tracheidal, with spiral or annular thickenings, endotegmen tanniniferous; n = 4, 5, 8-10, 12, 13; germination phanerocotylar.

10[list]/300: Hibbertia (115, Madagascar to Fiji, but nearly all endemic to Australia), Dillenia (60), Tetracera (40). Tropical and warm temperate (Map: from van Steenis & van Balgooy 1966; van Balgooy 1975; Heywood 1978). [Photos - Collection]

• Dilleniaceae are recognisable by the often strong and parallel secondary veins that proceed straight into the teeth; scalariform tertiary venation is common, and the lamina is often rough; the leaves tend to elongate when they are still rolled up. The bark is often rich brown. The pedicels are articulated near the apex and persist after the flower falls off; the flowers themselves are often conspicuous and have crumpled petals and numerous stamens that are reflexed in bud and often have porose anthers. The fruits are shiny follicles containing arillate seeds; the calyx is persistent, sometimes accrescent, and the filaments are also persistent.

The phytophagous tortricid Phricanthini are known only from Dilleniaceae (Powell et al. 1999).

Relationships in the family are [Tetracera (lianes) [Doliocarpus, Davilla, etc. (peltate stigma) [Dillenia (amplexicaul petiole) + Hibbertia]]] (Horn 2002). Note that Tetracera has reticulate perforation plates in its smallest vessels, the stomata are paracytic, and the endotesta seems to be in general poorly differentiated (Horn 2006). There are often sclereids in the pith.

Hibbertia, with some 115 species, is very variably both vegetatively and florally. Some taxa have very much reduced leaves and winged, photosynthetic stems, and stamen number varies from one to well over 150.

See Kubitzki (1971) and especially Horn (2006, but 4 subfamilies for 10 genera seems a bit excessive...) for general information.

Synonymy: Hibbertiaceae J. Agardh, Soramiaceae Martynov