The families of flowering plants
Habit and leaf form. Small trees, or shrubs. Leaves deciduous; alternate; petiolate; non-sheathing; simple. Lamina entire; ovate; pinnately veined; cross-venulate. Leaves stipulate. Stipules intrapetiolar; caducous (lanceolate). Lamina margins dentate (denticulate).
Leaf anatomy. Stomata present; anomocytic.
Axial (stem, wood) anatomy. Secondary thickening developing from a conventional cambial ring.
The vessel end-walls oblique; scalariform (with many cross bars). The parenchyma absent.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in inflorescences; in umbels. Inflorescences axillary; long pedunculate, globose, 2530 flowered umbels, the pedicels jointed in the middle; initially with involucral bracts (the involucre of 45 small, deciduous members); more or less pseudanthial. Flowers small; regular; 5–7 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; extrastaminal; of separate members (57 glands, opposite the corolla members alternatively interpretable as staminodes).
Perianth with distinct calyx and corolla; 10–14; 2 whorled; isomerous. Calyx 5–7; 1 whorled; gamosepalous (the linear, pubescent sepals shortly united at the base). Calyx lobes markedly longer than the tube. Calyx persistent; valvate. Corolla 5–7; 1 whorled; polypetalous, or gamopetalous (? the petals linear, indistinguishable from the sepals or slightly narrower); valvate; regular; persistent.
Androecium 5–7, or 10–14 (if the nectaries are interpreted as staminodes). Androecial members free of the perianth; free of one another; 1 whorled, or 2 whorled (if taken to include the nectary glands). Androecium exclusively of fertile stamens, or including staminodes (if the nectary glands are seen as staminodal). Staminodes 5–7; in the same series as the fertile stamens, or internal to the fertile stamens (antepetalous). Stamens 5–7 (persistent); isomerous with the perianth; oppositisepalous; erect in bud. Anthers dehiscing via longitudinal slits; tetrasporangiate. Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colporate (colporoidate).
Gynoecium 3 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled, or 3 celled (at the base). Gynoecium syncarpous; eu-syncarpous; superior. Ovary 1 locular (though with partial partitions at the base). Gynoecium stylate. Styles 1; attenuate from the ovary; apical. Stigmas 1; small, capitate. Placentation free central. Ovules in the single cavity 6 (borne atop the columnar, free central placenta); ascending.
Fruit non-fleshy; tardily dehiscent; a capsule (tomentose); 1 seeded (small, oblong, with a persistent style, surrounded by the persistent calyx, corolla and androecium).
Geography, cytology. Paleotropical. Sub-tropical, tropical. Northeast India, southern China and Burma.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgrens Superorder Violiflorae; Violales. Cronquists Subclass Rosidae; Santalales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Huertiales.
Species 1. Genera 1; only genus, Dipentodon.
Illustrations. • Dipentodon sinicus (Hutchinson).
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: 24th October 2017. delta-intkey.com/angio’.