Stenodrepanum

Taxonomy

Stenodrepanum H.A.T. Harms Notizbl. Bot. Gart. Berlin-Dahlem 7: 500. 1 Mar 1921.

Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.1.35.
Tribe: Caesalpinieae.
Group: Caesalpinia.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legumelegume:
usually dry, dehiscent fruit derived from a single carpel that opens along two longitudinal sutures
; unilocular; 2–4 cm long; 0.1–0.2 cm wide; 0.1 cm thick; more than 9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; curved to 1.5-coiled; not plicate; twisted; asymmetrical; linear; not inflated; terete; without beak; long tapered at apex; aligned 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; margin constricted along both margins; margin without sulcus; margin plain; wing(s) absent; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; active; with valves breaking. Replum invisible. Epicarp dull; monochrome; brown; with surface texture uniform; glabrous; eglandular; without spines; not smooth; with elevated features; veined; longitudinally veined relative to fruit length; not tuberculate; glandular dotted; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp absent. Endocarp present; visible; dull; opaque; monochrome; brown; without adhering pieces of testa; nonseptate; not exfoliating; entire. Seed(s) 1–7; length parallel with fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.1–0.7 mm long; of 1 length only; filiform; contorted. Aril absent.

Seed: 4–6 mm long; 1.3–1.7 mm wide; 0.5–0.7 mm thick; not overgrown; not angular; symmetrical; linear; 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; not modified by a bloom; colored; mottled; brown and tan; with black overlay; glabrous; not smooth; with elevated features; pustulate (?); coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines present; transverse reticulate. Rim absent. Wing(s) absent. Raphe visible (to 0.5 mm long). Hilum present; fully concealed; concealed by funicular remnant; without faboid split; punctiform; subapical to radicle tip (nearly marginal); recessed; not within corona, halo, or rim. Lens discernible; 0.1–0.3 mm long; with margins straight; triangular; not in groove of raphe; flush; similar color as testa; darker than testa; not within corona, halo, or rim. Endosperm present; thick; not pluglike and not resembling tip of radicle; 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; with lobes; with lobes not touching; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis straight; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; centered between cotyledons. Plumule rudimentary; glabrous.

Distribution

Argentina.

New World; South America (Argentina); Argentina and Brazil.

Generic Notes

The radicle-Cotyledon length ratio of 1:3 (using imbibed embryos) is unusual in the Caesalpinioideae. The usual ratio is greater than 1:5. Ulibarri (1979) monographed Stenodrepanum.