Family Huaceae

Huaceae A. Chev.

Habit and leaf form. Shrubs, or lianas, or herbs. Leaves alternate; short petiolate; aromatic (garlic-scented); simple. Lamina entire; pinnately veined; cross-venulate. Leaves stipulate. Stipules intrapetiolar; free of one another; caducous (small in Hua, larger in Afrostyrax). Lamina margins entire.

Leaf anatomy. Stomata present; paracytic.

Lamina without secretory cavities.

Stem anatomy. Secretory cavities absent. Nodes tri-lacunar. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with vessels. Vessel end-walls oblique; simple, or scalariform and simple. Vessels without vestured pits. Wood parenchyma paratracheal.

Reproductive type, pollination. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary; when aggregated, in fascicles (few flowered). Inflorescences axillary. Flowers small; calyptrate, or not calyptrate; regular; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk absent.

Perianth with distinct calyx and corolla; (9–)10; 2 whorled; isomerous, or anisomerous. Calyx 5, or 3–5; 1 whorled; polysepalous (Hua), or gamosepalous (the five sepals distinct in Hua, the calyx of Afrostyrax closed in the bud and opening by 3–5 irregular lobes); calyptrate (Afrostyrax), or not calyptrate; of Hua valvate. Corolla (4–)5 (the petals pubescent); 1 whorled; polypetalous; induplicate valvate. Petals long clawed (Hua), or sessile (more or less, in Afrostyrax — with a very short, broad base beneath the obovate blade).

Androecium (8–)10. Androecial members free of the perianth; all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens (8–)10; isomerous with the perianth. Anthers basifixed (peltate); bilocular (Hua), or four locular (in Afrostyrax, the inner locules much shorter than the outer); tetrasporangiate; appendaged (Afrostyrax), or unappendaged (Hua). The anther appendages in Afrostyrax, apical. Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; porate.

Gynoecium 5 carpelled. Carpels isomerous with the perianth. The pistil 1 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 1 locular. Gynoecium stylate. Styles 1; apical. Stigmas 1; small. Placentation basal. Ovules in the single cavity 1 (Hua), or (4–)6 (Afrostyrax); ascending; anatropous; bitegmic.

Fruit non-fleshy (dry); dehiscent (Hua), or indehiscent (Afrostyrax); a capsule, or capsular-indehiscent. Capsules in Hua, valvular. Seeds copiously endospermic (the endosperm smelling of garlic). Endosperm ruminate. Seeds large. Embryo well differentiated. Cotyledons 2 (broad, flattened).

Physiology, biochemistry. Proanthocyanidins absent. Ellagic acid absent.

Geography, cytology. Paleotropical. Tropical. Tropical Africa.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Malviflorae; Malvales. Cronquist’s Subclass Dilleniidae; Violales. APG 3 core angiosperms; core eudicot; Superorder Rosanae; fabid; Order Oxalidales.

Species 3. Genera 2; Afrostyrax, Hua.