Amherstia

Taxonomy

Amherstia N. Wallich Pl. Asiat. Rar. 1: 1. Sep 1829 ('1830').

Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.4.75.
Tribe: Detarieae.
Group: Amherstia.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume; unilocular; 12.5–15 cm long; 4–4.5 cm wide; 0.5–1.2 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; curved; not plicate; not twisted; symmetrical, or asymmetrical; oblanceolate, or falcate (only near the apex); with both sutures parallelly curved; not inflated; flattened; without beak; long tapered at apex; oblique with longitudinal axis of fruit; tapered at base; oblique with longitudinal axis of fruit; with the apex and base uniform in texture; ligneous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate; with the stipe 6–20 mm long; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures (initially along the ventral margin); apical and down; active; with valves separately enrolling. Replum invisible. Epicarp dull; monochrome; brown; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; not veined; not tuberculate; obliquely striate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; ligneous. Endocarp present; visible; dull; opaque; monochrome; tan; without adhering pieces of testa; nonseptate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 4–6; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.1–1.5 mm long; of 1 length only; thick; straight. Aril absent.

Seed: 15–27 mm long; 15–23 mm wide; 5–7 mm thick; not overgrown; not angular; symmetrical; ovate to circular, or irregular; compressed; 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; glossy to dull; not modified by a bloom; colored; monochrome; brown; glabrous; not smooth; with elevated features; rugose; coriaceous (thicker along the margin). Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; fully concealed; concealed by funicular remnant; without faboid split; larger than punctiform; 0.1–3 mm long; with curved outline; elliptic; apical at apex of radicle tip; flush; not within corona, halo, or rim. Lens not discernible. Endosperm absent. Cotyledons smooth; both outer faces convex; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; completely concealing radicle; notched at radicle and split over radicle; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis straight; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; centered between cotyledons. Plumule rudimentary; glabrous.

Distribution

Burma (Now widely cultivated).

Old World; Indochina (Burma).

Tropical worldwide crop.

Tribal Notes

Tribe Detarieae

Bruneau et al. (2000) carried out extensive phylogenetic analyses of tribes Amherstieae and Detarieae. They concluded that they form a single monophyletic group. Therefore, they supported Polhill's (1995a, 1995b) decision to unite the two tribes.