The families of flowering plants.
Habit and leaf form. Trees, or shrubs. Leaves deciduous; alternate; shortly petiolate; densely red gland-dotted (beneath); simple. Lamina entire; pinnately veined, or palmately veined (sometimes three nerved at the base). Leaves stipulate. Lamina margins entire.
Stem anatomy. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Vessel end-walls scalariform and simple. Primary medullary rays narrow.
Reproductive type, pollination. Plantsdioecious. Gynoecium of male flowers pistillodial (the pistillode small).
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in spikes, or in catkins. The ultimate inflorescence unit racemose. Inflorescences axillary (more or less precocious); rather short, catkinlike spikes or racemes. Flowers regular; 4–6 merous; cyclic. Free hypanthium absent. Hypogynous disk absent.
Perianthsepaline; 4–6; 1 whorled. Calyx 4–6; 1 whorled; polysepalous (the sepals narrow, in the female flowers), or partially gamosepalous to gamosepalous (sometimes irregularly gamosepalous in the male flowers); imbricate.
Androecium 4–6. Androecial members free of the perianth; free of one another, or coherent; 1 whorled. Androecium of male flowers exclusively of fertile stamens. Stamens 4–6; isomerous with the perianth; oppositisepalous; filantherous (the filaments short and spreading). Anthers dehiscing via longitudinal slits; extrorse (and often bearing a dorsal gland). Pollen shed as single grains. Pollen grains resembling those of Celtis.
Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil2 celled. Gynoecium syncarpous; synovarious; superior.Ovary 2 locular (compressed at right angles to the plane of the septum). Gynoecium stylate. Styles 2; long, free. Placentation apical. Ovules 2 per locule; pendulous; anatropous.
Fruit non-fleshy; a schizocarp. Mericarps 2; samaroid (in the form of two winged or winglike cocci, separating from the persistent central axis). Seeds sparsely endospermic; flat.
Geography, cytology. Paleotropical and Cape. Sub-tropical to tropical. Tropical and South Africa, Southeast Asia, Malay Peninsula, Sumatra.
Taxonomy.Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Urticales. Cronquist’s Subclass Rosidae; Euphorbiales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Malpighiales (as a synonym of Euphorbiaceae).
Species 5. Genera 1; only genus, Hymenocardia.
General remarks. This description is scarcely adequate.