The families of flowering plants.
Habit and leaf form. Trees and shrubs; with coloured juice. Mesophytic, or xerophytic. Leaves alternate; petiolate; non-sheathing; gland-dotted, or not gland-dotted; aromatic, or without marked odour; simple. Lamina dissected; palmatifid; palmately veined; cross-venulate. Leaves stipulate. Lamina margins serrate. Leaves without a persistent basal meristem.
Leaf anatomy. Mucilaginous epidermis often present.
Minor leaf veins without phloem transfer cells (Cochlosperma).
Stem anatomy. Secretory cavities present (in the cortex and pith); with mucilage. Cortical bundles absent. Medullary bundles absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. The secondary phloem stratified into hard (fibrous) and soft (parenchymatous) zones. ‘Included’ phloem absent. Xylem with fibre tracheids. Vessels without vestured pits (but with vestured fibre pits). Wood partially storied (VPI), or not storied; parenchyma predominantly apotracheal.
Reproductive type, pollination. Plants hermaphrodite.
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in panicles and in racemes. Inflorescences paniculate or racemose. Flowers large; regular to somewhat irregular. Free hypanthium absent.
Perianth with distinct calyx and corolla; 8, or 10; 2 whorled; isomerous. Calyx 4, or 5; 1 whorled; polysepalous; not persistent (deciduous); imbricate. Corolla 4, or 5; 1 whorled; polypetalous; imbricate, or contorted; yellow.
Androecium 15–100 (‘many’). Androecial members branched (with trunk bundles); maturing centrifugally; free of the perianth; all equal to markedly unequal; free of one another. Androecium exclusively of fertile stamens. Stamens 15–60; polystemonous. Anthers dehiscing via pores (these apical, often confluent). Pollen grains aperturate; 3 aperturate; colporate; 2-celled.
Gynoecium 3–5 carpelled. The pistil 1 celled, or 3 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 1 locular, or 3 locular. Styles 1; attenuate from the ovary; apical. Stigmas 1 (minute). Placentation when unilocular, parietal; when trilocular, axile. Ovules in the single cavity when unilocular, 20–100 (i.e. ‘many’); when trilocular, 20–50 per locule (i.e. ‘many’); anatropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Endosperm formation nuclear.
Fruit non-fleshy; dehiscent; a capsule. Capsules three to five valvular. Seeds endospermic. Endosperm oily. Cotyledons 2. Embryo straight, or curved, or coiled. Micropyle zigzag.
Physiology, biochemistry. Proanthocyanidins present; cyanidin. Flavonols present; kaempferol, quercetin, and myricetin. Ellagic acid present (Cochlospermum). Saponins/sapogenins present. Aluminium accumulation not found.
Geography, cytology. Tropical. Widespread-tropical, except Malaysia.
Taxonomy.Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Malvales. Cronquist’s Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Malvales (as a synonym of Bixaceae?).
Species 20–25. Genera 2; Amoreuxia, Cochlospermum.