Chamaecrista

Taxonomy

Chamaecrista C. Moench Meth. 272. 4 Mai 1794.

Subfamily: Caesalpinioideae.
Phylogenetic Number: 1.2.18.
Tribe: Cassieae.
Subtribe: Cassiinae.
Species Studied - Species in Genus: 51 studied; ca. 265 in genus.

Description

Fruit: A legume; unilocular; 0.4–19 cm long; 0.3–3 cm wide; 0.2 cm thick; 2–9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight to curved; not plicate; not twisted; asymmetrical; linear to oblong; not inflated; compressed; without beak; long tapered at apex; aligned with longitudinal axis of fruit; short tapered at base to rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; chartaceous to ligneous; seed chambers externally invisible, or visible; margin not constricted; margin without sulcus; margin plain, or embellished (rarely); margin with wing(s); wing(s) rarely present; wing(s) 2; wing(s) 0.1 mm wide (?); wing(s) sutural; wing(s) on both sutures; substipitate; with all layers dehiscing (elastically); splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves breaking, or revolute (stated as "spirally coiled or fracturing"). Replum invisible. Epicarp dull to glossy; monochrome; brown to reddish brown, or black, or purple; with surface texture uniform; glabrous to pubescent and indurate (stated as viscid); with hairs erect; with simple hairs; eglandular; without spines; not smooth; with elevated features; veined, or not veined; reticulately veined; not tuberculate; shagreen; exfoliating in part; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present, or absent; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; ligneous to chartaceous. Endocarp present; visible; dull; opaque; monochrome; greenish brown to tan; without adhering pieces of testa; septate to subseptate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 1–19; length oblique to fruit length; neither overlapping nor touching; in 1 series. Funiculus 0.1–1 mm long; of 1 length only; thick; triangular. Aril absent.

Seed: 3.5–7 mm long; 1.7–5 mm wide; 1–2 mm thick; not overgrown; angular, or not angular; symmetrical; linear, or lanceolate, or elliptic, or ovate, or circular, or oblong, or cordate, or triangular, or quadrangular, or rectangular, or D-shaped, or reniform, or irregular, or C-shaped, or trapezoid, or rhombic, or pyriform (lanceolate, ovate, quadrangular, triangular); 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; monochrome; light to dark or orange brown, or black; glabrous; smooth, or not smooth; with elevated features, or recessed features; shagreen, or pustulate ("blistered"); striate, or pitted with small separate pits, or cracked ("usually lineolate to serially or randomly pitted and minutely transversely or longitudinally crackled"); osseous. Pleurogram absent. Pseudopleurogram absent. Fracture lines present, or absent; reticulate. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible, or fully concealed; concealed by funicular remnant; without faboid split; punctiform; subapical to radicle tip to marginal according to radicle tip; flush; not within corona, halo, or rim. Lens discernible; 0.1–0.3 mm long; with margins curved; elliptic to circular; not in groove of raphe; round or mounded; similar color as testa; lighter than testa, or 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; notched at radicle; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis straight to oblique; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; centered between cotyledons. Plumule moderately developed; glabrous.

Distribution

Generic Notes

Greene (1897) named many of the studied species. Irwin and Barneby (1976) evaluated the generic status of Chamaecrista, and Irwin and Barneby (1978) monographed sections Absus and Grimaldia. They noted that seeds of Cassia polita Irwin & Barneby, now Chamaechrista polita (Irwin & Barneby) Irwin & Barneby, may be "distally encrusted with exudate." Seeds of studied species placed overnight in the softening solution consistently had cuticles that separated into minute patches, which enrolled along their margins. Irwin and Barneby (1982) noted the cuticle for some species "in age peeling in scurfy flakes, mucilaginous when wetted".