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The families of flowering plants

L. Watson and M.J. Dallwitz

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.

Axial (stem, wood) anatomy. Secretory cavities absent. Nodes tri-lacunar. Internal phloem absent. Secondary thickening developing from a conventional cambial ring.

The vessel end-walls oblique; simple, or scalariform and simple. The vessels without vestured pits. The parenchyma paratracheal. ‘Included’ phloem absent.

Reproductive type, pollination. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary; when aggregated, in fascicles (these 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, phytochemistry. 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 III core angiosperms; core eudicot; Superorder Rosanae; fabid. APG IV Order Oxalidales.

Species 3. Genera 2; Afrostyrax, Hua.

Illustrations. • Hua gabonii (Hutchinson). • Hua parvifolia, = ?: Bot. Jahrb. Syst. 45 (1912). • Afrostyrax kamerunensis: Bot. Jahrb. Syst. 43 (1910).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 5th March 2018.’.