Enterolobium

Taxonomy

Enterolobium C.F.P. von Martius Flora 20(2)(Beibl.): 117. 21 Nov 1837.

Subfamily: Mimosoideae.
Phylogenetic Number: 2.5.07.
Tribe: Ingeae.
Species Studied - Species in Genus: 4 studied; 10 in genus.

Description

Fruit: A legume; unilocular; 6–17 cm long; 2–9 cm wide; 0.7–2 cm thick; length less than twice as long as width, or 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; 0.5-coiled to 1-coiled to 1.5-coiled to 2-coiled; not plicate; not twisted; symmetrical, or asymmetrical; C-shaped; with both sutures parallelly curved; not inflated; compressed; without beak; rounded at apex; aligned with longitudinal axis of fruit; rounded at base; oblique with longitudinal axis of fruit; with the apex and base uniform in texture; when young fleshy and ligneous (upon drying); seed chambers externally visible (to faintly visible); margin constricted; margin slightly constricted only on 1 margin (ventral margin slightly constricted and dorsal margin not constricted); margin without sulcus; margin plain; wing(s) absent; nonstipitate; indehiscent (valves remaining attached to sutures). Replum invisible. Epicarp dull to glossy; monochrome; black to brown (reddish); with surface texture uniform; glabrous; eglandular; without spines; smooth to not smooth; with elevated features; not veined; not tuberculate; shagreen; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; surface not veined; 1-layered; without balsamic vesicles; without reniform canals; spongy (when young), or solid (when mature). Endocarp present; visible; dull to glossy; opaque; monochrome; brown; without adhering pieces of testa; septate; not exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 5–14; length transverse to fruit length; neither overlapping nor touching; in 1 series, or 2 or more series (2 series). Funiculus up to 20 mm long (alternately longer and shorter to accommodate 2 rows of seeds); of 1 length only, or 2 different lengths (alternately longer and shorter funiculi); crumpled thick; plicate to coiled. Aril absent.

Seed: 9–23 mm long; 3.5–15 mm wide; 3–9.5 mm thick; not overgrown; not angular; symmetrical; elliptic (to indented on each side and appearing squeezed due to pressure of adjacent seeds); compressed to terete; 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; monochrome to bichrome; reddish brown (and when sometimes bichrome light brown on pleurogram and adjacent testa); glabrous; smooth; osseous (with tendency to shatter). Pleurogram present; 100 %. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; fully concealed; concealed by funicular remnant; without faboid split; punctiform; apical at apex of radicle tip; flush; not within corona, halo, or rim. Lens discernible; 0.3–1 mm long; with margins straight, or curved; irregular; ovate to elliptic; not in groove of raphe; mounded; dissimilar color from testa; yellow; not within corona, halo, or rim. Endosperm absent. Cotyledons smooth; both outer faces flat; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; completely concealing radicle; with lobes; with lobes overlapping; with basal groin formed by lobes; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis straight; slightly oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; straight with embryonic axis; centered between cotyledons. Plumule well developed; glabrous.

Distribution

West Indies, Central and South America.

New World; Mexico, West Indies, Central America, and South America; Argentina, Peru, Brazil, Ecuador, and the Guianas.

Generic Notes

Enterolobium fruits are unusual in the subfamily, especially those fruits with seeds in two series (B). Barneby and Grimes (1996) reviewed the systematics of the genus, and referred to an unpublished M.S. thesis by A. de L. Mesquita submitted to the Universidade Federal Rural de Pernambuco in 1990. The fruits of E. cyclocarpum (Jacq.) Griseb. have been described as 'anachronistic' because they supposedly evolved for dispersal by Pleistocene megafauna that are now extinct (Barlow 2000).