Plant a shrub or tree; true roots +, origin endogeneous, root cap +, apex multicellular; endodermis +; shoot apical meristem multicellular; lateral meristems +, cork cambium producing cork abaxially, vascular cambium producing phloem abaxially and xylem adaxially; lamina with mean venation density 1.8 mm/mm2 (to 5 mm/mm2).
EXTANT SEED PLANTS/SPERMATOPHYTA
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 derived from (some) sinapyl and particularly coniferyl alcohols, thus containing p-hydroxyphenyl and guaiacyl lignin units, so no Maüle reaction; root xylem exarch, cork cambium deep seated; arbuscular mycorrhizae +; shoot apical meristem interface specific plasmodesmatal network; stem with vascular tissue around central pith [eustele], vascular bundles with interfascicular tissue, ectophloic, endodermis 0, xylem endarch; 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 +; stem cork cambium superficial; branches exogenous; leaves with single trace from vascular sympodium ["nodes 1:1"]; vascular bundles collateral [stem: phloem external; leaf: phloem abaxial]; stomata morphology?, pore opening controlled by abscisic acid; leaves with petiole and lamina, spiral, development basipetal, blade simple; axillary buds +, not associated with all leaves; prophylls two, lateral; plant heterosporous, sporangia borne on sporophylls; microsporophylls aggregated in indeterminate cones/strobili; true pollen +, grains mono[ana]sulcate, exine and intine homogeneous; ovules unitegmic, parietal tissue 2+ cells across, 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, developing after pollination, with cell walls, flagellae numerous; ovules increasing considerably in size between pollination and fertilization, female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large" [ca 8 mm3], but not much bigger than ovule, with morphological dormancy; embryo cellular ab initio, endoscopic, plane of first cleavage of zygote transverse, suspensor +, short-minute, embryo straight, shoot and root at opposite ends [allorrhizic], white, cotyledons 2; plastid transmission maternal; ycf2 gene in inverted repeat, two copies of LEAFY gene, PHY gene duplications [three - [BP [A/N + C/O]] - copies], nrDNA with 5.8S and 5S rDNA in separate clusters; mitochondrial nad1 intron 2 and coxIIi3 intron and trans-spliced introns present.
Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], S [syringyl] lignin units common, positive Maüle reaction [syringyl:guaiacyl ratio more 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, exodermis +; shoot apex with tunica-corpus construction, tunica 2-layered; reaction wood ?, associated gelatinous fibres [g-fibres] with innermost layer of secondary cell wall rich in cellulose and poor in lignin; 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, cytoplasm not occluding pores of sieve plate, companion cell and sieve tube from same mother cell; sugar transport in phloem passive; nodes unilacunar [1:?]; stomata brachyparacytic [ends of subsidiary cells level with ends of pore], outer stomatal ledges producing vestibule; lamina formed from the primordial leaf apex, margins toothed, development of venation acropetal, secondary veins pinnate, overall growth ± diffuse, venation hierarchical, fine venation reticulate, veins (1.7-)4.1(-5.7) mm/mm2, endings free; most/all leaves with axillary buds; flowers perfect, pedicellate, ± haplomorphic, parts spiral [esp. the A], free, numbers unstable, development in general centripetal; P not sharply differentiated, with a single trace, outer members not enclosing the rest of the bud, often smaller than inner members; A many, filament not sharply distinguished from anther, stout, broad, with a single trace, anther introrse, tetrasporangiate, sporangia in two groups of two [dithecal], ± embedded in the filament, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally, endothecium +, endothecial cells elongated at right angles to long axis of anther; tapetum glandular, cells binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, tectum continuous or microperforate, ektexine columellar, endexine thin, compact, lamellate only in the apertural regions; nectary 0; G superior, free, several, ascidiate, with postgenital occlusion by secretion, stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, carinal, dry [not secretory]; 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 [crassinucellate], nucellar cap?; megasporocyte single, hypodermal, megaspore tetrad linear, functional megaspore chalazal, lacking sporopollenin and cuticle; female gametophyte 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 binucleate at dispersal, male gametophyte trinucleate, germinating in less than 3 hours, pollination siphonogamous, tube elongated, growing between cells, growth rate 20-20,000 µm/hour, outer wall pectic, inner wall callose, 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, flagellae 0, double fertilization +, ovules aborting unless fertilized; P deciduous in fruit; seed exotestal, becoming much larger than ovule at time of fertilization; endosperm diploid, cellular [micropylar and chalazal domains develop differently, 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; embryogenesis cellular; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)n]; 2C genome size 1-8.2 pg [1 pg = 109 base pairs], whole genome duplication, 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, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and three copies of the PHY gene, [PHYB [PHYA + PHYC]].
[NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]]: vessels +, elements with elongated scalariform perforation plates; 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]]]]: essential oils in specialized cells [lamina and P ± pellucid-punctate]; tension wood 0; tectum reticulate; anther wall with outer secondary parietal cell layer dividing; carpels plicate; nucellar cap + [character lost where in eudicots?]; 12BP [4 amino acids] deletion in P1 gene.
[[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]] / MESANGIOSPERMAE: benzylisoquinoline alkaloids +; polyacetate derived anthraquinones + [?level]; outer epidermal walls of root elongation zone with cellulose fibrils oriented transverse to root axis; P more or less whorled, 3-merous [possible positiion]; embryo sac bipolar, 8 nucleate, antipodal cells persisting; endosperm triploid; ?germination.
[MONOCOTS [CERATOPHYLLALES + EUDICOTS]]: (veins in lamina often 7-17mm/mm2 or more [mean for eudicots 8.0]); (stamens opposite [two whorls of] P); (pollen tube growth fast).
[CERATOPHYLLALES + EUDICOTS]: ethereal oils 0.
EUDICOTS: myricetin, delphinidin scattered, asarone 0 [unknown in some groups, + in some asterids]; root epidermis derived from root cap [?Buxaceae, etc.]; nodes 3:3; stomata anomocytic; flowers (dimerous), cyclic; K/outer P members with three traces, "C" with a single trace; A few, (polyandry widespread, initial primordia 5, 10, or ring, ± centrifugal), filaments fairly slender, anthers basifixed; microsporogenesis simultaneous, pollen tricolpate, apertures in pairs at six points of the young tetrad [Fischer's rule], cleavage centripetal, wall with endexine; G with complete postgenital fusion, stylulus/style solid [?here]; seed coat?
[PROTEALES [TROCHODENDRALES [BUXALES + CORE EUDICOTS]]]: (axial/receptacular nectary +).
[TROCHODENDRALES [BUXALES + CORE EUDICOTS]]: benzylisoquinoline alkaloids 0; euAP3 + TM6 genes [duplication of paleoAP3 gene: B class], mitochondrial rps2 gene lost.
[BUXALES + CORE EUDICOTS]: ?
CORE EUDICOTS / GUNNERIDAE: (ellagic and gallic acids +); leaf margins serrate; compitum + [one place]; micropyle?; palaeohexaploidy [gamma triplication], PI-dB motif +, small deletion in the 18S ribosomal DNA common.
[ROSIDS ET AL. + ASTERIDS ET AL.] / PENTAPETALAE: root apical meristem closed; (cyanogenesis also via [iso]leucine, valine and phenylalanine pathways); flowers rather stereotyped: 5-merous, parts whorled; P = calyx + corolla, the calyx enclosing the flower in bud, sepals with three or more traces, petals with a single trace; stamens = 2x K/C, in two whorls developing internally/adaxially to the corolla whorl and successively alternating, (numerous, but then usually fasciculate and/or centrifugal); pollen tricolporate; G , G  also common, when [G 2], carpels superposed, compitum +, placentation axile, style +, stigma not decurrent; endosperm nuclear; fruit dry, dehiscent, loculicidal [when a capsule]; RNase-based gametophytic incompatibility system present; floral nectaries with CRABSCLAW expression.
Evolution. Divergence & Distribution. The age of this clade has been estimated at some 113 m.y. (Leebens-Mack et al. 2005, but see sampling); Anderson et al. (2005) suggest a similar figure (stem group to 116 m.y. old, crown group diversification by ca 109 m.y.); Chaw et al. (2004: 61 chloroplast genes, sampling poor) date the crown group to 115-110 m.y.a., and Magallón and Castillo (2009) around 114.5 m.y.. Moore et al. (2010: 95% highest posterior density, see also N. Zhang et al. 2012) suggest crown-group ages of (113-)109(-104) m.y. Bell et al. (2010) ages of (124-)121, 117(-97) m.y., and Magallón et al. (2013: with temporal constraints) ages of (115.9-)110.5-109(-103) m.y. for this clade.
The oldest known core eudicot macrofossil, unfortunately not attributed to any extant group, is the Rose Creek fossil from the Cretaceous-Cenomanian, a mere 96-94 m.y.a. (Basinger & Dilcher 1984). The flower is relatively large compared to the tiny flowers so common in early Cretaceous angiosperms. The five stamens are opposite the petals and there is a well developed nectary, the earliest in the fossil record (Friis et al. 2011).
Endress (2011a) suggested that the presence of compitum in rosids and the extended clade including asterids might be key innovations for each; Dilleniaceae do not have a compitum. It seems preferable to peg the character at this node; Dilleniaceae would then have lost a compitum, although if Dilleniaceae turn out to be sister to the combined clades, things will be simpler. However, Gunneraceae, at least, also have a compitum, and so one can argue that presence of compitum could be placed one node more basally... Five-merous flowers and the distinction between sepals and petals are other potential key innovations, whatever the position of Dilleniaceae (Endress 2011a).
The flowers of Pentapetalae are very distinctive, as indicated by the characterisation above. Five-merous flowers preponderate (hence the name "pentapetalae"), and they are uncommon in more basal clades (González & Mello 2009). Sepals usually have three traces and petals have one, while three-trace petals are sometimes to be found in other eudicots, magnoliids, etc. There is considerable discussion as to the distinction between and evolution of sepals and petals. Petals here may generally be derived from tepals, perhaps ultimately from bracts, not from stamens (perhaps with some exceptions, as in Caryophyllaceae, etc.: Ronse de Craene 2007, 2008). The duplication of a number of genes important in determining the identity of the parts of pentapetalous flowers (AP3, AP1, SEP, AG) may be connected with the gamma genome triplication event that is an apomorphy for the core eudicots (Jiao et al. 2012; vekemans et al. 2012). Compared to many eudicots in more basal clades, the two perianth whorls are distinctive in that members of each encircle the floral axis, all members of the androecial whorls being adaxial/interior to the petals.
Taxa that have flowers with many stamens are scattered throughout the core eudicots. The stamens usually develop on common primordia, whether a ring primordium or five or ten separate primordia, when five, the primordia are often opposite the petals, rather than alternating with them. Numerous individual stamens then develop from these few initial primordia, and development is often centrifugal (c.f. esp. magnoliids and the ANITA grade). At maturity, the stamens themselves may be more or less connate or in fascicles (especially Corner 1946b; Weberling 1989; Leins 2000 and references; Prenner et al. 2008). There can be considerable variation in staminal development between closely related multistaminate taxa (e.g. Hufford 1990; Ge et al. 2007). Polyandry is less common in the [asterid I + asterid II] clade (q.v. for discussion) and it appears to be of a rather different nature there.
Tentatively, then, and based entirely on gross morphology, there seem to have been major changes in floral organisation at the angiosperm node, the monocot node, the Pentapetalae node, the asterid node, and perhaps the [asterid I + asterid II] node. As noted above, the floral morphology of extant Gunnerales is very different from that of Pentapetale and is more similar to that of the eudicots immediately basal to them.
For the floral development of Berberidopsis corallina and Aextoxicon (Berberidopsidales), possible "links" in the evolution of the flower of core eudicots, see Ronse De Craene (2004, 2007, 2010). The link is at best thought of as an analogy, since several elements of this floral morphology are probably parallelisms within core eudicots and others may even be reversals; there is considerable variation in floral morphology in this small clade. Berberidospidales are part of the pectination immediately basal to asterids, relationships perhaps being [Santalales [Berberidopsidales [Caryophyllales + asterids]]] (see below). Chase (2005) noted that in Santalales some floral parts, particularly stamens, might have several whorls, and this perhaps suggested that canalisation of floral development there was less than in some other core eudicots; whether Santalales really are different in this respect from other core eudicot groups remains to be established. Clarification of the phylogenetic position of Dilleniales, etc., will undoubtedly help in our understanding of floral evolution.
Chemistry, Morphology, etc. The distribution of ellagic acid is similar to that of common primordium-type polyandry in the eudicots. Sampling of variation in the root apical meristem is poor, and possible reversals (for which, see Groot et al. 2004) have not been placed on the tree. Lee et al. (2004) suggest that the CRABS CLAW gene is expressed in core eudicot nectaries (including extrafloral nectaries), or at least in the rosids and asterids that they sampled; it was not expressed in nectaries of Ranunculaceae; what happens in Proteaceae, which has axial nectaries, like rosids (e.g. Smets 1988) and Sabiaceae is unfortunately unknown. This gene is not expressed in the extrafloral nectaries of Passifloraceae (Krosnick et al. 2008a). Seed coats with a mechanical layer more than a single cell thick occur throughout BLAs, but again, seed coats of the [asterid I + asterid II] clade are rather different, usually being only one or two cells across.
Phylogeny. This clade is strongly supported, e.g. Chase et al. (1993), D. Soltis et al. (1997, 1999, 2003a), Hoot et al. (1998), and Nandi et al. (1998), but support is rather weaker in Zhu et al. (2007). Within this large clade, although the rosid and asterid clades are well supported, other relationships have long been unclear, there being a six-radiate polytomy (see the sixth and earlier versions of this site) involving Crossosomatales, Berberidopsidales, Caryophyllales, Santalales, rosids and asterids; Dilleniales and Saxifragales were also of uncertain positions. D. Soltis et al. (2003a: four-gene analysis) suggested that Berberidopsidales were sister to the rest of the non-rosid core eudicots, but they has only 54% jacknife support. Santalales were associated with asterids, while Saxifragales and Vitales linked with [Dilleniales + Caryophyllales], but with still less support (D. Soltis et al. 2003a). In some studies Dilleniaceae were sister to Caryophyllales, but with only very moderate support; D. Soltis et al. (2003a) provided rather stronger (83% jacknife) support for this position (see also Soltis et al. 2007a: 1.0 p.p.). It also seemed possible that [Caryophyllales + Dilleniales] and Santalales formed a clade (D. Soltis et al. 2000); Carlquist (2006) suggested that non-bordered perforation plates was a possible similarity between Santalales and Caryophyllales. Caryophyllales were linked with with asterids in a large 18S ribosomal DNA analysis (Soltis et al. 1997), albeit with only weak support (see also Hilu et al. 2003).
In studies using whole chloroplast genomes (Jansen et al. 2006a, esp. 2006b; Hansen et al. 2007; Cai et al. 2007; Ruhlman et al. 2006; Jansen et al. 2007; Moore et al. 2007; Logacheva et al. 2008) support for a [Caryophyllales + asterids] clade was stronger, however, Berberidospidales, Dilleniales, Santalales and Saxifragales were not included. [Caryophyllales + Santalales] were sister to asterids in some analyses in a study that focused on the position of Cynomoriaceae and Balanophoraceae (Nickrent et al. 2005: again, see sampling). In a study using the mitochondrial gene matR, Caryophyllales repeated as sister to asterids, but with very little support; in other analyses including a reduced sampling and two chloroplast genes Santalales and Dilleniales were also in this area, but again with little support (Zhu et al. 2007). In the combined morphological and molecular study of Nandi et al. (1998) the position of Caryophyllales was uncertain, but this was perhaps partly because the ovules of Rhabdodendraceae, there sister to all other Caryophyllales, were interpreted as being unitegmic; however, subsequent work suggested that Rhabdodendraceae are not sister to all other Caryophyllales, but are embedded in the order (see Caryophyllales page).
In any event, it was becoming increasingly likely that Caryophyllales, whether or not accompanied by a number of other taxa, were sister to asterids (but c.f. Goloboff et al. 2009). There was support for placing Crossosomatales as sister to the core malvid group (Huerteales, Sapindales, etc.: see Zhu et al. 2007; Soltis et al. 2011, etc.). In a two-gene study focussing of early-diverging eudicots, Dilleniales, Berberidopsidales, Santalales and Caryophyllales grouped in a pectinate fashion with the asterids, although support was low (Hilu et al. 2008). Wang et al. (2009: 12-gene plus plastid inverted repeat) in a study of the rosids found that Berberidopsidales was sister to a clade made up of the few Caryophyllales and asterids they had included. Moore et al. (2008) in a preliminary analysis of whole-chloroplast genome data, suggested that most members of the basal polytomy of the core eudicots could be placed as a series of pectinate branches immediately basal to the asterids; Moore et al. (2010, see also 2011) suggested the relationships [Santalales [Berberidopsidales [Caryophyllales + Asterids]]], the position of Caryophyllales having the least support. Relationships in Bell et al. (2010) were [Berberidopsidales [Caryophyllales, Santalales, asterids]], in Soltis et al. (2011: little bootstrap support), [Santalales [[Berberidopsidales + Caryophyllales] + asterids]], i.e. their superasteridae, and in Arakaki et al. (2011), [Santalales [Berberidopsidales [Caryophyllales + Asterids]]]. These are all consistent with many of the earlier, more tentatively suggested relationships.
Some morphological evidence, including seed coat anatomy, might suggest a relationship between Dilleniales and Vitales. Horne (2006) listed a number of features linking Dilleniaceae and Rhabdodendraceae (then thought to be sister to the rest of Caryophyllales), some of which could be features of [Dilleniales + Caryophyllales], and the status of the others depended on an improved resolution of relationships. These features include absence of tension wood; successive cambia present; vessel elements with simple perforation plates; wood with SiO2 bodies; nodes 3 or more:3 or more; leaves spiral; K persistent in fruit. However, recent work suggests that Rhabdodendraceae are sister to the core Caryophyllales and immediately associated families rather than sister to all Caryophyllales (e.g. Drysdale et al. 2007; Brockington et al. 2007).
The position of Dilleniales has remained uncertain. Bell et al. (2010) placed it sister to Caryophyllales and Soltis et al. (2011) in a broadly similar position as sister their superasteridae, and with 87% ML bootstrap support; this position was also found by Arakaki et al. 2011), who included a larger sample of caryophyllalean chloroplast genomes. Similarly Qiu et al. (2010) found a weakly supported [Dilleniales + Berberidopsidales] clade sister to an [asterid [Santalales + Caryophyllales]] clade, but also with very weak support. Moore et al. (2008) suggested that Dilleniales were sister to rosids, although support could be stronger, while Moore et al. (2011) found a weakly supported [Dilleniales [rosids s.l. + asterids s.l.]] clade. Dilleniaceae are near basal somewhere in Pentapetalae, but are best left unplaced for now.
For further discussion, see Caryophyllales, asterids, and Saxifragales.
Classification. In Versions 8 and earlier of this site this was called the the core eudicot clade, largely because the evolution of the "typical" core eudicot flower can be pegged to this node; the current delimitation of core eudicots refers to a clade that is molecularly well supported but that is perhaps morphologically less interesting.
[DILLENIALES [SAXIFRAGALES [VITALES + ROSIDS s. str.]]]: nodes 3:3; stipules + [usually apparently inserted on the stem].
Evolution. Moore et al. (2010: 95% highest posterior density) suggest ages of (112-)108(-103) m.y. for the crown group.
DILLENIALES Berchtold & J. Presl Main Tree.
A many, often centrifugal; G separate, compitum 0; ?micropyle; fruit a follicle; endotesta ± palisade, massively lignified, exotegmen usu. tracheidal. - 1 family, 10 genera, 300 species.
Note: Possible apomorphies are now being added throughout the site; they are in bold. However, the actual level at which many of these features, particularly the more cryptic ones, should be assigned is unclear. This is because there is very considerable homoplasy for many characters, with with variation within and between clades. Furthermore, basic information for all too many characters is very incomplete, often coming from taxa well embedded in the clade of interest and so making the position of any putative apomorphy uncertain. Then there is the not-so-trivial issue of how ancestral states are reconstructed...
Evolution. Divergence & Distribution. The stem age may be ca 114.75 m.y. and the crown age only ca 52.45 m.y. (Magallón & Castillo 2009).
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 vascular cylinder; (successive cambia +); cork cambium deep-seated; (vessel elements with simple perforation plates); true tracheids +; raphides +, also common in wood; rays often broad; epidermis silicified; branching from previous flush; hairs unicellular; leaves spiral, lamina vernation conduplicate, surface often scabrid, margins toothed, secondary veins parallel, proceeding straight to the teeth [percurrent], tertiary venation ± scalariform, fine veins areolate, teeth with clear glandular expanded apex, base rather broad, stipules 0, long petiolar flanges + (0); inflorescence?; pedicels articulated; K (3-)5(-20), (with 1 trace), C (2-)5, crumpled in bud (not); androecium often asymmetric, A (2-)many, from a ring primordium or fasciculate, fascicles opposite K, 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 petals, or odd member adaxial), styluli long, stigmas capitate to punctate, wet [1 record]; ovules 1-many/carpel, apotropous, often campylotropous (straight), micropyle zigzag or exostomal, outer integument 2(-3) cells across, inner integument 2-6 cells across, parietal tissue 6-14 cells across, nucellar cap ca 2 cells across, chalazal area massive; (megaspore mother cells several); (fruit a nut; berry), (K enclosing fruit, ± fleshy); aril +, funicular, often laciniate, exotesta often fleshy, exotegmen with spiral or annular thickenings, endotegmen tanniniferous; zygote with distinctive wall and protrusions into the endosperm ["mantle"]; n = 4, 5, 8-10, 12, 13; germination phanerocotylar.
10[list]/300-410 - four groups below. Tropical and warm temperate (map: from van Steenis & van Balgooy 1966; van Balgooy 1975; Heywood 1978; Trop. Afr. Fl. Pl. Ecol. Distr. 1. 2003; Horn 2009). [Photos - Collection.]
1. Delimoideae Burnett
Lianes; stomata paracytic.
1/44 (Tetracera). Pantropical.
[Doliocarpoideae [Hibbertioideae + Dillenioideae]]: ?
2. Doliocarpoideae J. W. Horn
(Compitum +), stigma infundibular; ovules 2/carpel, collateral, one epitropous, the other apotropous.
5/65: Doliocarpus (40). Neotropical.
[Hibbertioideae + Dillenioideae]: ?
3. Hibbertioideae J. W. Horn
Nodes 1:1, 3:3; (hairs stellate); (lamina entire), tertiary venation ± random, areoles at most weakly developed; (flowers [horizontally] monosymmetric); A 1-200+ (outer staminodes +; obdiplostemonous, the outer A basally connate).
1/115-225. Madagascar to Fiji, but nearly all endemic to Australia.
4. Dillenioideae Burnett
Cork cambium superficial; leaf base surrounding stem; (flowers [horizontally] monosymmetric); A very numerous [200+]; G many, (compitum +); (exotestal cells large, tanniniferous, becoming flattened - Dillenia).
4/75. Dillenia (60). Madagascar to Fiji, most Indo-Malesian, few Australia.
Evolution. Plant-Animal Interactions. Caterpillars of the tortricid Phricanthini moths are known only from Dilleniaceae (Powell et al. 1999).
Pollination Biology & Seed Dispersal. Buzz pollination is likely to be common in Dilleniaceae (Endress 1997b).
The dispersal unit is generally the seed, which may be arillate and then endozoochorous (Dillenia) or myrmecochorous, as in most of the rest of the family (Lengyel et al. 2009, 2010).
Chemistry, Morphology, etc. There are often sclereids in the pith. Hibbertia is very variable both vegetatively and florally. Some species have very much reduced leaves and winged, photosynthetic stems, floral symmetry varies, and stamen number varies from one to well over 150. The monosymmetric flowers of Didesmandra aspera have two bundles of stamens on the functionally upper side of the flower, in each there is a single fertile stamen longer than the rest; the flower is drawn as if the plane of symmetry in horizontal (Stapf 1900); the monosymmetric flowers of Schumacheria have only a single staminal bundle in which all stamens are about the same lengths.
See Kubitzki (1971) and especially Horn (2006, 2009) for general information, Paetow (1931), Sastri (1958) and Swamy and Periasamy (1955) for floral morphology, embryology, etc., and Tucker and Bernhardt (2000) for floral development in Hibbertia.
Phylogeny. For relationships, I follow Horn (2002, 2009). Tetracera has reticulate perforation plates in its smallest vessels and its endotesta seems to be poorly differentiated (Horn 2006); if the latter in particular is confirmed, adjustments to clade characterizations may be in order.
Classification. See Horn (2009).
Synonymy: Delimaceae Martius, Hibbertiaceae J. Agardh, Soramiaceae Martynov