Diphysa

Taxonomy

Diphysa N. von Jacquin Enum. Pl. Carib. 7, 28. Sep-Nov 1760.

Subfamily: Faboideae.
Phylogenetic Number: 3.14.03.
Tribe: Aeschynomeneae.
Subtribe: Ormocarpinae.
Species Studied - Species in Genus: 8 studied; 15 in genus, or 20 in genus.

Description

Fruit: A legume; unilocular; 3–6.5 cm long; 0.7–3 cm wide; 0.7–3 cm thick (estimated); 2–9 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; not plicate; not twisted; symmetrical; linear, or oblong; inflated; terete; without beak; short tapered at apex to rounded at apex; aligned with longitudinal axis of fruit; long tapered at base, or rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; membranous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain, or embellished; margin with wing(s); wing(s) present, or absent; wing(s) 1; wing(s) sutural (subwinged or keeled); wing(s) on 1 suture; stipitate, or substipitate; with the stipe 5–15 mm long; indehiscent. Replum invisible. Epicarp dull; monochrome; brown, or tan; with surface texture uniform; glabrous; without spines; not smooth; with elevated features; veined; longitudinally veined relative to fruit length (with faint cross veining), or reticulately veined; not tuberculate; not exfoliating; with cracks to without cracks; cracking irregular; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent. Endocarp present; visible; dull; opaque; monochrome; tan; scurfy; without adhering pieces of testa; nonseptate; coriaceous; not exfoliating; remaining fused to epicarp; with wing(s) extending into epicarp, or without wings; entire. Seed(s) few, probably less than 5; length oblique to fruit length; neither overlapping nor touching; in 1 series. Funiculus of 1 length only; filiform; straight. Aril absent.

Seed: 4–7 mm long; 2.7–4.5 mm wide; 1.5–3.3 mm thick; not overgrown; not angular; asymmetrical; oblong; terete to compressed; with visible radicle and cotyledon lobes, or without visible radicle and cotyledon lobes; with external groove between radicle and cotyledon lobes; with external groove between radicle and cotyledon lobes same color as testa; 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; modified by a bloom; colored; monochrome; dark reddish brown to tan; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Raphe visible; from hilum to near base of seed and terminating; not bifurcating; color of testa; raised to recessed. Hilum present; visible to partially concealed; concealed by funicular remnant; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform to larger than punctiform; 0.1–0.5 mm long; with curved outline; circular; subapical to radicle tip, or between cotyledon and radicle lobe; recessed; within rim, or not within corona, halo, or rim; rim color of testa. Lens not discernible. Endosperm present; thick to thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa. 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; split over radicle; with lobes; with lobes not touching; with the interface division terminating at base of radicle; without margins recessed; yellow, or green (ish); inner face flat; glabrous on inner face. Embryonic axis right angled; perpendicular to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; linear; lobe tip straight; deflexed and parallel to cotyledon width; centered between cotyledons; less than 1/2 length of cotyledons. Plumule moderately developed to well developed; glabrous.

Distribution

Mexico, Central America, northern South America.

New World; United States to Mexico to Central America to South America (northern).

Generic Notes

Tribal and subtribal placement of Diphysa is based on Lavin (1987; Polhill, 1994a, 1994b), and not on Polhill and Sousa (1981), who placed Diphysa in Robinieae.

Tribal Notes

Tribe Aeschynomeneae

Rudd (1981a) recognized four subtribes of Aeschynomeneae: Ormocarpinae V.E. Rudd (genera 3.14.01–3.14.08), Aeschynomeninae (genera 3.14.09–3.14.16), Discolobinae (A.E. Burkart) V.E. Rudd (genus 3.14.17: Discolobium), Poiretiinae (A.E. Burkart) V.E. Rudd (genera 3.14.18–3.14.21), and Stylosanthinae (G. Bentham) V.E. Rudd (genera 3.14.22–13.4.26). Tribal and subtribal placement of Diphysa is based on Lavin (1987; Polhill, 1994a, 1994b), and not on Polhill and Sousa (1981), who placed Diphysa in Robinieae. Bailey et al. (1997), using the chloroplast rpl2 intron and ORF184, suggested that Brya (11.01), Cranocarpus (11.02), Phylacium (11.22), and Neocollettia (11.26) are not members of Desmodieae (11) and that they probably belong in Aeschynomeneae.