Diphyllarium

Taxonomy

Diphyllarium F. Gagnepain Notul. Syst. (Paris) 3: 183. 25 Dec 1915.

Subfamily: Faboideae.
Phylogenetic Number: 3.10.37.
Tribe: Phaseoleae.
Subtribe: Glycininae.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume; unilocular; 6.3–8 cm long; 0.7 cm wide; 0.3–4 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; slightly asymmetrical; nearly linear; with both sutures nearly straight; not inflated; flattened; without beak; tapered at apex; oblique with longitudinal axis of fruit; tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; leathery; seed chambers externally barely visible; margin constricted; margin slightly constricted along both margins; margin without sulcus; margin embellished; margin with ridge(s); wing(s) absent; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves twisting. Replum invisible. Epicarp dull; monochrome; drying dark brown to black; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; not veined; not tuberculate; slightly rugose; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome; dark brown to black; smooth; without adhering pieces of testa; subseptate; with septa thin (tissue paper-like), flexible; with septa eglandular; chartaceous; exfoliating in part; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 7–8; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.5–1.5 mm long; of 1 length only; flattened; triangular. Aril present; dry; when dry rim-aril and tongue-aril; entire; covering less than 1/2 of seed; cream.

Seed: 6.2 mm long; 5 mm wide; 2.5 mm thick; not overgrown; not angular; asymmetrical; elliptic; 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; mottled; with infrequent mottles; dark brown; with brown overlay (lighter); glabrous; smooth; chartaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; partially concealed; concealed by aril; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; larger than punctiform; 1.5 mm long; with curved outline; elliptic; apical according to radicle tip but marginal according to seed length; recessed; within rim; rim color of testa. Lens discernible; 1 mm long; with margins straight; linear; not in groove of raphe; confluent with hilum; flush; same color as testa; not within corona, halo, or rim. Endosperm absent. Cotyledons not smooth; sulcate; 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; without lobes; with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis oblique; perpendicular to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; linear; lobe tip curved; deflexed and parallel to cotyledon width; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Indochina.

Old World; Indochina and Indonesia and the Philippines.

Generic Notes

Fruits studied were immature and from the same specimen.

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.