Piptadeniastrum Brenan, Kew Bull. 10: 179. 1955.

Figs 120, 121, 122, 125

Type.

Piptadeniastrum africanum (Hook. f.) Brenan [≡ Piptadenia africana Hook. f.]

Description.

Tall trees, unarmed, with ramified, aliform buttresses often more than 3 m high (Fig. 120H, I). Stipules linear, densely pubescent, 5.5-9 mm long, apex sharp, caducous. Leaves (Fig. 121F) bipinnate, eglandular; pinnae often alternate, 10-19 (23) pairs per leaf; leaflets (26) 30-58 (61) pairs per pinna, sessile, linear or falcate, apex obtuse, base asymmetric. Inflorescence (Fig. 121I, J) a panicle of fascicled spiciform racemes, terminal. Flowers (Fig. 121I) pedicellate with abscission zone near pedicel apex, bisexual, yellow or yellowish-white; calyx gamosepalous, cupuliform, distinctly toothed; petals free, glabrous, adnate basally with the stamens and a perigynous disc forming a stemonozone; stamens 10, filaments red, anther connective terminating in a large globular, sessile, caducous gland; pollen tricolporate, finely reticulate, dispersed as monads; ovary glabrous, red, ovules 9, style slender, stigma porate and slightly dilated. Fruit (Fig. 122K) flattened, straight to slightly curved, dehiscent along a single suture, the valves remaining attached along the other, exocarp coriaceous. Seeds (Fig. 122L) flattened, surrounded by a broad membranous wing, oblong, funicle inserted near the middle of a long margin.

Chromosome number.

2 n = 26, diploid (Lewis and Elias 1981; Santos et al. 2012).

Included species and geographic distribution.

One species, P. africanum, in tropical Africa, from Liberia and Guinea east to South Sudan and Uganda, and south to Angola (Fig. 125).

Ecology.

Rainforest and in riparian vegetation within more seasonally dry tropical forest.

Human uses.

Used for commercial timber, charcoal, fish and rodent poison, in traditional medicines and in rituals (Luckow 2005).

Notes.

In his revision of the African members of Piptadenia (sensu Baker 1930), Brenan (1955) created the segregate monospecific genus Piptadeniastrum to house Piptadeniastrum africanum, a tall, unarmed tree from west-central sub-Saharan Africa reminiscent of Newtonia Baill. in its fruits that dehisce along one suture while the valves remain attached along the other, and in its winged seeds, though differing in its often-alternate pinnae, glabrous floral structures and point of funicular attachment at the middle edge of the longest axis of the seed.

Taxonomic references.

Brenan (1959); Villiers (1989).