Leptodesmia

Taxonomy

Leptodesmia (G. Bentham) G. Bentham & J.D. Hooker Gen. 1: 522. 19 Oct 1865.

Subfamily: Faboideae.
Phylogenetic Number: 3.11.20.
Tribe: Desmodieae.
Subtribe: Desmodiinae.
Species Studied - Species in Genus: 2 studied; 3 in genus.

Description

Fruit: A legume; unilocular; 0.3–0.5 cm long; 0.2–0.35 cm wide; 0.05 cm thick; length less than twice as long as width; with deciduous androecial sheath; with deciduous corolla; with persistent calyx; with calyx longer than fruit, or shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; asymmetrical; oblong to circular (sub); with both sutures parallelly curved; not inflated; flattened; with beak (persistent style,Du Puy et al., 2002), or without beak; straight; with solid beak the same color and texture as fruit; rounded at apex; oblique with longitudinal axis of fruit to right-angled 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; seed chambers with the raised seed chambers not torulose; margin not constricted; margin without sulcus; margin plain; wing(s) absent; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along 1 suture; medial and up and down; active; with valves reflexing. Replum invisible. Epicarp dull; monochrome; reddish brown; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; puberulent; with pubescence gray; 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; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome; golden brown; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1; length parallel with fruit length. Funiculus flattened; straight. Aril present; fleshy; when fleshy cupshaped; entire; covering less than 1/2 of seed; reddish brown, or cream.

Seed: 2–2.5 mm long; 1–1.5 mm wide; 0.5–0.8 mm thick; not overgrown; not angular; asymmetrical; reniform; 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, or dull; not modified by a bloom; colored; mottled and streaked, or monochrome; with frequent mottles; with frequent streaks; dark to lighter reddish brown, or green, or olive; with black overlay; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; fully 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; 0.5 mm long; with curved outline; elliptic; marginal according to radicle tip; flush; within rim; rim color of testa. Lens discernible (under aril); with margins curved; circular; not in groove of raphe; confluent with hilum; mounded; dissimilar color from testa; darker than testa; black; not within corona, halo, or rim. Endosperm present; 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; 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; linear; deflexed and parallel to cotyledon length; centered between cotyledons; less than 1/2 length of cotyledons, or 1/2 to nearly length of cotyledons. Plumule moderately developed; glabrous.

Distribution

Madagascar (5 spp.) and India (L. congesta).

Old World; Madagascar and India (L. congesta).

Generic Notes

Du Puy et al. (2002) effectively revised this genus because all the species occur in Madagascar. They reduced the genus to just three species, and their species count is used.

Tribal Notes

Tribe Desmodieae

Ohashi et al. (1981) started their treatment of the Desmodieae with these thoughts: "A sensible classification of Desmodieae is prejudiced by the traditional over-weighting of fruit characters." (sic) "The fruit normally consists of indehiscent jointed articles, but fruits that open have arisen at least seven times..." They supplemented their text with a fruit-seed plate. They placed Brya and Cranocarpus (11.02), the only two New World endemic genera, in the new subtribe Bryinae, "characterized most notably by glochidiate hairs." Bailey et al. (1997), using the chloroplast rpl2 intron and ORF184, suggested that Brya, Cranocarpus, Phylacium (11.22), and Neocollettia (11.26) are not members of Desmodieae and that they probably belong in Aeschynomeneae (14).