Aextoxicaceae Engl. and Gilg
Habit and leaf form. Large trees. Leaves alternate (to subopposite); spiral; petiolate; non-sheathing; simple. Lamina entire; cross-venulate. Leaves exstipulate. Lamina margins entire.
Leaf anatomy. Hairs present. Complex hairs lepidote.
Stem anatomy. Secondary thickening developing from a conventional cambial ring. Xylem with tracheids. Vessel end-walls scalariform. Vessels without vestured pits.
Reproductive type, pollination. Fertile flowers functionally male, or functionally female. Plants dioecious. Female flowers without staminodes. Gynoecium of male flowers pistillodial, or vestigial. |
Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes. The ultimate inflorescence unit racemose. Inflorescences axillary (lepidote). Bracts (or rather, single bracteoles) calyptrate. Flowers calyptrate; regular; 5 merous; cyclic. Free hypanthium absent. Hypogynous disk present; of separate members (5).
Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; polysepalous; not persistent (deciduous); imbricate. Corolla 5; 1 whorled; polypetalous; imbricate. Petals spathulate, broadly clawed.
Androecium 5. Androecial members free of the perianth; all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 5; oppositisepalous. Anthers dehiscing via short slits (above); introrse. Pollen grains aperturate; 3 aperturate; colporate.
Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary 2 locular. Styles 1 (shortly bifid). Stigmas 2. Placentation apical. Ovules 2 per locule (but only one loculus fertile); pendulous; non-arillate; bitegmic; crassinucellate. Outer integument not contributing to the micropyle.
Fruit non-fleshy (small); indehiscent; a drupe. The drupes with one stone (one-seeded). Fruit 1 seeded. Seeds endospermic. Endosperm ruminate. Cotyledons 2 (these flattened, cordate-orbicular).
Physiology, biochemistry. Saponins/sapogenins absent.
Geography, cytology. Chile. N = 16.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Euphorbiales (?). Cronquist’s Subclass Rosidae; Celastrales. APG (1998) Eudicot; core Eudicot; neither Rosid nor Asterid. APG 3 (2009) Order: Berberidopsidales.
Species 1. Genera 1; only genus, Aextoxicon.
Illustrations.
• Technical details.
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