Piptanthus

Taxonomy

Piptanthus R. Sweet Brit. Fl. Gard. 264. 1828.

Subfamily: Faboideae.
Phylogenetic Number: 3.29.02.
Tribe: Thermopsideae.
Species Studied - Species in Genus: 2 studied; 2–3 in genus.

Description

Fruit: A legume; unilocular; 7–9 cm long; 1–1.3 cm wide; 0.18–0.2 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with persistent calyx, or deciduous calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; S-curved to contorted (to slightly curved); not plicate; not twisted; asymmetrical, or symmetrical; linear; with both sutures nearly straight; not inflated; flattened; without beak; tapered at apex, or short tapered at apex; aligned with longitudinal axis of fruit, or 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 visible; margin constricted, or not constricted; margin constricted along both margins (not regularly); margin without sulcus; margin plain; wing(s) absent; stipitate, or substipitate; with the stipe 5–20 mm long; with all layers dehiscing, or with epicarp and mesocarp breaking near center of valve and endocarp dehiscing along suture; splitting along suture(s). Dehiscence of valves passive. Replum invisible. Epicarp dull; monochrome; brown, or tan (and brown over seeds); with surface texture uniform; pubescent and indurate; with hairs appressed, or erect; with 1 type of pubescence; strigose; with pubescence gray-brown (P. tomentosa A.R. Franchet), or golden (P. nepalinsis); with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; veined; reticulately veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; quite thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; fleshy. Endocarp present; visible; dull; opaque; bichrome; dark brown; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; separating into 1-seeded winged segments. Seed(s) 2–10; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 3 mm long; of 1 length only; thick; straight. Aril absent.

Seed: 5–7 mm long; 4.3–5 mm wide; 1.5–3.5 mm thick; not overgrown; not angular; asymmetrical; oblong (with radicle lobe); compressed; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; 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 and streaked; with frequent mottles; with frequent streaks; greenish or reddish brown, or tan (reddish); with brown overlay (reddish), or green overlay; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe visible; from hilum through lens and terminating before base of seed; not bifurcating; darker than testa; brown; raised. Hilum present; 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; larger than punctiform, or punctiform; 0.3–0.7 mm long; with curved outline; circular; between cotyledon and radicle lobe; recessed; within rim; rim color of testa, or darker than testa. Lens discernible; 0.5–1 mm long; with margins curved; circular; not in groove of raphe; adjacent to hilum; 1.3–1.5 mm from hilum; mounded; dissimilar color from testa; darker than testa; dark brown; not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to testa (and a sheath around radicle). 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; not concealing radicle; entire over radicle; without lobes; with the interface division terminating at base of radicle; without margins recessed; tan; inner face flat; glabrous on inner face. Embryonic axis deflexed; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; deflexed and parallel to cotyledon length, or deflexed and parallel to cotyledon width; centered between cotyledons; less than 1/2 length of cotyledons. Plumule moderately developed; glabrous.

Distribution

India, Nepal, and China.

Old World; India to China (India (and Nepal)).

Generic Notes

Turner (1980), who monographed the genus, recognized two species, but Turner (1981) noted the species number as two or three. We noticed that the area under the hilum is thick and spongy.

Tribal Notes

Tribe Thermopsideae

Yong-Ming and Ze-Xiang (1990) reevaluated the six genera and forty-seven species in the tribe, and their data confirms Turner (1981). Turner recognized forty-six species and six genera in the tribe.