Piptadeniastrum

Taxonomy

Piptadeniastrum J.P.M. Brenan Kew Bull. 1955: 179. 12 Sep 1955.

Subfamily: Mimosoideae.
Phylogenetic Number: 2.3.08.
Tribe: Mimoseae.
Group: Newtonia.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume; unilocular; 25–36 cm long; 2–3.5 cm wide; 0.2–0.4 cm thick; more than 9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight to curved; not plicate; not twisted; symmetrical; broadly linear; not inflated; flattened; without beak; short tapered at apex; right-angled with longitudinal axis of fruit; short tapered at base to rounded at base (nearly); aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate; with the stipe up to 10 mm long; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along 1 suture (along ventral suture and remaining united along dorsal suture); medial and up and down; passive. Replum invisible. Epicarp dull; monochrome; dark brown; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; not veined, or veined; on the ventral half of valves regularly and obliquely veined relative to fruit length and irregularly veined (on the dorsal half of valves); not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent. Endocarp present; visible; dull; opaque; monochrome; reddish brown; smooth; without adhering pieces of testa; nonseptate; not exfoliating; entire. Seed(s) 6–14; length parallel with fruit length; overlapping; in 1 series. Funiculus 10–20 mm long; of 1 length only; filiform; S-curved. Aril absent.

Seed: 30–100 mm long; 15–30 mm wide; 1 mm thick; not overgrown; not angular; symmetrical; oblong; flattened; with surface smooth; without visible radicle and cotyledon lobes; without hilar sinus; without umbo on seed faces; without medial ridge on each face. Cuticle not exfoliating; not inflated; not wrinkled. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; dull to glossy; not modified by a bloom; colored; monochrome; brown; glabrous; not smooth; with elevated features; rugose; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) present; continuous around seed (up to 20 mm wide (widest at base), sometimes notched at 1 or both ends). Raphe not visible. Hilum present; fully concealed; concealed by wing; without faboid split; punctiform; apical according to radicle tip but marginal according to seed length; flush; not within corona, halo, or rim. Lens not discernible. Endosperm absent. Cotyledons smooth; both outer faces flat; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; not concealing radicle; notched at radicle; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis slightly deflexed; perpendicular to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; straight with embryonic axis; centered between cotyledons. Plumule moderately developed; glabrous.

Distribution

Senegal to Sudan and Angola.

Old World; Africa (Senegal to Sudan and Angola).

Generic Notes

Based on seed characters this species is not a Newtonia s.s. Fruit characters also support this segregate genus. The venation pattern arising from the central suture of this species is similar to the pattern arising from the dorsal suture of Newtonia s.s.