Family Diegodendraceae

Diegodendraceae Capuron

~ Bixaceae

Habit and leaf form. Small trees, or shrubs. Leaves alternate; non-sheathing; densely, minutely gland-dotted; aromatic (smelling of camphor when crushed); simple. Lamina entire; lanceolate. Leaves stipulate. Stipules intrapetiolar; caducous (fairly large, convolute, leaving annular scars). Lamina margins entire.

Stem anatomy. Vessels with vestured pits.

Reproductive type, pollination. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in panicles. Inflorescences terminal; few-flowered terminal panicles with alternate branches. Flowers bracteate; bracteolate; large; fragrant; regular. Free hypanthium absent. Hypogynous disk absent (?).

Perianth with distinct calyx and corolla; 10 (usually), or 12; 2 whorled; isomerous. Calyx 5(–6); 1 whorled; polysepalous (the sepals unequal); persistent. Corolla 5(–6); 1 whorled; polypetalous (the petals large, slightly unequal); imbricate; deciduous.

Androecium 30–100 (‘many’). Androecial members free of the perianth; free of one another. Androecium exclusively of fertile stamens. Stamens 30–100 (‘many’); polystemonous; filantherous (the filaments filiform). Anthers basifixed (ovate-oblong); non-versatile; dehiscing via longitudinal slits; latrorse.

Gynoecium 1–4 carpelled. Carpels reduced in number relative to the perianth. The pistil (1–)2–4 celled. Gynoecium syncarpous; synstylous (deeply lobed, the bodies of the carpels free, with a common, central, gynobasic style — cf. Ochnaceae); superior. Carpel 2 ovuled. Placentation basal. Ovary (1–)2–4 locular (but the ‘locules’ separated). Gynoecium stylate. Styles 1; ‘gynobasic’ (central). Stigmas 1; punctiform. Placentation basal. Ovules 2 per locule; ascending; apotropous; with ventral raphe (with the micropyles facing outwards); collateral; anatropous.

Fruit unknown.

Geography, cytology. Paleotropical. Tropical. Madagascar.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Malvales. Cronquist’s Subclass Dilleniidae; Theales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; malvid; Order Malvales (as a synonym of Bixaceae).

Species 1. Genera 1; only genus, Diegodendron.

RbcL sequence analyses indicate close affinity with Bixa (Fay et al, 1998).