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The families of flowering plants

L. Watson and M.J. Dallwitz

Dilleniaceae Salisb.

Including Hibbertiaceae J.G. Agardh

Habit and leaf form. Trees, shrubs, and lianas, or herbs (a few). ‘Normal’ plants, or switch-plants (occasionally); switch plants with the principal photosynthesizing function transferred to stems. Leaves well developed (usually), or much reduced. Plants green and photosynthesizing. With a basal aggregation of leaves (sometimes), or without conspicuous aggregations of leaves. Self supporting, or climbing; sometimes stem twiners; Hibbertia recorded as reversibly twining clockwise, or twining anticlockwise. Sometimes leptocaul. Mesophytic, or xerophytic. Leaves usually deciduous; alternate (usually), or opposite (rarely); usually spiral; leathery (often), or ‘herbaceous’, or membranous; petiolate; sheathing, or non-sheathing; gland-dotted, or not gland-dotted; simple. Lamina entire (usually), or dissected (occasionally lobed); one-veined, or pinnately veined, or palmately veined. Leaves stipulate (the stipules winglike, adnate to the petiole), or exstipulate. Lamina margins entire, or serrate. Leaf development not ‘graminaceous’. Domatia occurring in the family (known from two genera); manifested as pockets, or hair tufts.

General anatomy. Plants with ‘crystal sand’, or without ‘crystal sand’.

Leaf anatomy. Stomata anomocytic (usually), or paracytic (Tetracera). The mesophyll with sclerenchymatous idioblasts, or without sclerenchymatous idioblasts. Minor leaf veins without phloem transfer cells (Dillenia).

Axial (stem, wood) anatomy. Young stems with solid internodes. Pith with diaphragms (occasionally), or without diaphragms. Cork cambium present; initially deep-seated (usually), or initially superficial. Nodes unilacunar, or tri-lacunar, or penta-lacunar to multilacunar (?). Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Secondary thickening developing from a conventional cambial ring, or anomalous (rarely?). The anomalous secondary thickening when present, via concentric cambia (Doliocarpus).

The wood ring porous to diffuse porous. The vessels medium (usually), or large (in the lianes); solitary (except for ostensible tangential pairs due to overlapping ends). The vessel end-walls scalariform, or scalariform and simple. The vessels without vestured pits. The axial xylem with tracheids; with fibre tracheids. The parenchyma predominantly apotracheal, or apotracheal and paratracheal (sometimes with a few cells around the vessels). ‘Included’ phloem present (in Doliocarpus), or absent. The wood not storied. Tyloses present, or absent.

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’. The ultimate inflorescence units when flowers aggregated, cymose, or racemose. Flowers small to medium-sized (usually), or large; regular to somewhat irregular. The floral irregularity when noticeable, involving the androecium. Flowers partially acyclic. The perianth acyclic, or the androecium acyclic, or the perianth acyclic and the androecium acyclic. Floral receptacle not markedly hollowed. Free hypanthium absent. Hypogynous disk absent.

Perianth with distinct calyx and corolla; (5–)10(–25). Calyx (3–)5(–20); polysepalous; fleshy, or non-fleshy; persistent; spirally imbricate. Corolla (2–)5; polypetalous; imbricate, or crumpled in bud (often); white, or yellow; deciduous (often conspicuously caducous). Petals bilobed, or entire.

Androecium 15–150 (usually), or 1–10 (rarely). Androecial members branched (usually — in that the numerous stamens often arise from 5–15 ‘trunks’), or unbranched; when numerous, maturing centrifugally (as a whole, or those within each cluster); free of the perianth; all equal to markedly unequal; free of one another, or coherent (often united basally); when clustered 1 adelphous, or 5–15 adelphous. Androecium exclusively of fertile stamens, or including staminodes. Stamens 1–10 (rarely), or 15–150 (usually ‘many’); reduced in number relative to the adjacent perianth to diplostemonous to polystemonous. Anthers usually basifixed, or adnate; dehiscing via pores to dehiscing via short slits (apically), or dehiscing via longitudinal slits; introrse, or latrorse; tetrasporangiate. Endothecium developing fibrous thickenings, or not developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or linear. Anther wall initially with more than one middle layer. Tapetum amoeboid, or glandular. Pollen grains aperturate; 2(–4) aperturate; colpate, or colporate, or rugate, or spiraperturate; 2-celled.

Gynoecium (1–)2–7(–20) carpelled. The pistil when syncarpous, (2–)5(–7) celled. Gynoecium apocarpous to syncarpous; eu-apocarpous to semicarpous (usually), or synovarious (rarely); superior. Carpel fully closed, or incompletely closed; stylate; apically stigmatic; 1–100 ovuled (i.e. to ‘many’). Placentation when apocarpous marginal, or basal. Ovary when syncarpous (2–)5(–7) locular. Styles as many as G; when carpels connate, free. Stigmas wet type; non-papillate; Group IV type. Placentation when syncarpous axile, or basal. Ovules when syncarpous, 1–20 per locule; ascending; apotropous; with ventral raphe; usually arillate; anatropous to amphitropous (with zigzag micropyle); bitegmic; crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped, or hooked (Hibbertia). Endosperm formation nuclear. Embryogeny onagrad.

Fruit non-fleshy; an aggregate, or not an aggregate. The fruiting carpel when apocarpous a follicle, or an achene, or baccate (?). Fruit when syncarpous dehiscent, or indehiscent (and then enclosed in the fleshy calyx); a capsule, or capsular-indehiscent; enclosed in the fleshy receptacle, or enclosed in the fleshy hypanthium, or without fleshy investment external to the original ovary. Seeds copiously endospermic. Endosperm oily. Embryo well differentiated (very small). Cotyledons 2. Embryo achlorophyllous (1/1); straight.

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. Anatomy non-C4 type (Dillenia). Sugars transported as sucrose, or as oligosaccharides + sucrose (in Dillenia). Not cyanogenic. Alkaloids absent (usually), or present (then not benzyl isoquinoline). Iridoids not detected. Saponins/sapogenins absent. Proanthocyanidins present; cyanidin and delphinidin. Flavonols present; quercetin, or kaempferol, quercetin, and myricetin. Ellagic acid absent (3 species, 2 genera). Aluminium accumulation not found. Sieve-tube plastids S-type.

Geography, cytology. Temperate (warm), sub-tropical to tropical. Pantropical and subtropical, and all Australia. X = 4, 5, 8, 10, 12, 13.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Dilleniales. Cronquist’s Subclass Dilleniidae; Dilleniales. APG III core angiosperms; core eudicot; unplaced at Superordinal level. APG IV Order Dilleniales.

Species 400. Genera 11; Acrotrema, Curatella, Davilla, Didesmandra, Dillenia, Doliocarpus, Hibbertia, Pachynema, Pinzona, Schumacheria, Tetracera.

Illustrations. • Le Maout and Decaisne: Hibbertia, Dillenia. • Hibbertia spp., as Hemistemma and Pleurandra: Lindley. • Tetracera alnifolia: Thonner. • Dillenia suffruticosa, as Wormia burbidgei: Bot. Mag. 106 (1880). • Hibbertia cuneiformis: flowers (photo). • Hibbertia cuneiformis: habitat (photo). • Hibbertia cuneiformis: Bot. Reg. 29 (50), 1843. • Hibbertia ericifolia: Hooker, Fl. Tasmaniae (1860). • Hibbertia racemosa: habit (photo). • Hibbertia racemosa: flowers and leaves (photo). • Hibbertia scandens: Bot. Mag. 449, 1799. • Hibbertia scandens: Bot. Mag. 449, text. • Hibbertia dentata: Bot. Reg. 282, 1818. • Hibbertia pedunculata: Bot. Reg. 1001, 1826. • Hibbertia perfoliata: Bot. Reg. 29 (64), 1843. • Acrotrema uniflorum: Hook. Ic. Pl. 2 (1837). • Didesmandra aspera: Hook. Ic. Pl. 27 (1900). • Schumacheria castaneaefolia: R. Wight (1840). • Schumacheria angustifolia: Trimen, Ill. Fl Ceylon (1893). • Hibbertia furfuracea, H. lepidota and Tetracera oblongata: leaf hairs (Solereder, 1908).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 5th March 2018.’.