Decorsea

Taxonomy

Decorsea R. Viguier Notul. Syst. (Paris) 14: 181. Nov 1951.

Subfamily: Faboideae.
Phylogenetic Number: 3.10.54.
Tribe: Phaseoleae.
Subtribe: Phaseolinae.
Species Studied - Species in Genus: 1 studied; 6 in genus.

Description

Fruit: A legume; unilocular; 7–15 cm long; 0.4–0.8 cm wide; more than 9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight, or curved (slightly); not plicate; not twisted; asymmetrical, or symmetrical; linear, or falcate; with both sutures parallelly curved; not inflated; compressed; without beak; tapered at apex; oblique with longitudinal axis of fruit; short tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally barely visible, or invisible; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin embellished; margin with thickened sutural areas; wing(s) absent; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; assumed apical and down; active; with valves twisting. Replum invisible. Epicarp dull; monochrome; pale brown to brown; with surface texture uniform; pubescent but soon deciduous, or glabrous (Du Puy et al., 2002); with hairs erect; puberulent; with simple hairs; eglandular; without spines; smooth; not veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thick; surface not veined; 1-layered; without balsamic vesicles; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome; white; smooth; without adhering pieces of testa; subseptate; with septa thin (tissue paper-like), flexible; with septa eglandular; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 5–14; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.5–0.7 mm long; of 1 length only; flattened; curved to triangular. Aril present, or absent (Du Puy et al., 2002); slightly fleshy to dry; when fleshy 2-lipped rim-aril; entire; covering less than 1/2 of seed; when dry 2-lipped rim-aril; entire; covering less than 1/2 of seed; with tongues (or flap) on lips of 2-lipped rim-aril; with 1 tongue or flap on 1 lip of 2-lipped rim-aril; cream.

Seed: 5.3–10.6 mm long; 3–5.5 mm wide; 2–4.5 mm thick; not overgrown; not angular; symmetrical, or asymmetrical; ovate to reniform, or oblong to elliptic (Du Puy et al., 2002); 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; dull; not modified by a bloom; colored; monochrome, or mottled; with frequent mottles; brown, or black; with brown overlay (darker); glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; partially concealed, or fully concealed; concealed by aril; without faboid split; larger than punctiform; 2.4–3.6 mm long; with curved outline; elliptic; apical according to radicle tip but marginal according to seed length; recessed; within rim, or within corona; corona color darker than testa; rim color darker than testa. Lens discernible; 0.1–0.7 mm long; with margins straight; linear; not in groove of raphe; confluent with hilum; flush; same color as testa; brown; not within corona, halo, or rim. Endosperm apparently 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; partially concealing radicle; notched at radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; pink; inner face flat; glabrous on inner face. Embryonic axis oblique; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; linear; lobe tip straight; oblique to cotyledons; centered between cotyledons; less than 1/2 length of cotyledons. Plumule well developed; glabrous.

Distribution

Southern and eastern Africa and Madagascar.

Old World; Africa and Madagascar.

Generic Notes

Verdcourt (1971) gave a more exact distribution for this genus. Du Puy et al. (2002) added another species to this genus, and their species count is used. There are three species in Southern Africa and three in Madagascar (Du Puy et al., 2002).

Tribal Notes

Tribe Phaseoleae

Bruneau et al. (1995) carried out cladistic analyses of tribe Phaseoleae using chloroplast DNA restriction site data. Their results indicated that the tribe is not monophyletic and that the tribal delimitations between Phaseoleae and Desmodieae (11) and between Phaseoleae and Millettieae (7) are problematic.