Microlobius

Taxonomy

Microlobius C.B. Presl Abh. Königl. Böhm. Ges. Wiss. ser. 5. 3: 496. Jul-Dec 1845.

Subfamily: Mimosoideae.
Phylogenetic Number: 2.3.21.
Tribe: Mimoseae.
Group: Piptadenia.
Species Studied - Species in Genus: 1 studied; 1 in genus.

Description

Fruit: A legume; unilocular; 2–10 cm long; 1–1.5 cm wide; 0.5–0.7 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; curved to 0.5-coiled; not plicate; not twisted; symmetrical, or asymmetrical; linear, or C-shaped; with both sutures parallelly curved; not inflated; compressed; without beak; short tapered at apex; aligned with longitudinal axis of fruit; tapered at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; ligneous; seed chambers externally visible; margin constricted; margin constricted along both margins (once), or slightly constricted along both margins; margin without sulcus; margin plain; wing(s) absent; stipitate, or substipitate; with the stipe up to 8 mm long; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along 1 suture (along dorsal margin, valves remaining attached to sutures); apical and down; passive. Replum invisible. Epicarp dull; monochrome; reddish brown; with surface texture uniform; pubescent and indurate; with hairs erect; with simple hairs; eglandular; without spines; not smooth; with elevated features; not veined, or veined (faintly); 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 fibers; without reniform canals; solid; ligneous. Endocarp present; visible; dull; opaque; monochrome; reddish brown; scurfy; without adhering pieces of testa; subseptate to nonseptate; exfoliating; remaining fused to mesocarp and epicarp; entire. Seed(s) 3–8; length parallel with fruit length to oblique to fruit length; neither overlapping nor touching; in 1 series. Funiculus 6–8 mm long; of 1 length only; thick; S-curved to plicate. Aril absent.

Seed: 5.5–9 mm long; 5.5–8 mm wide; 2–3 mm thick; not overgrown; not angular; symmetrical; circular to ovate, or irregular; 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; white to tan; glabrous; smooth; osseous to coriaceous. Pleurogram present; 50 %. 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; subapical to radicle tip; flush; not within corona, halo, or rim. Lens discernible; 0.5 mm long; with margins straight, or curved; rhombic; elliptic; not in groove of raphe; mounded to flush; same color as testa, or similar color as testa; lighter than testa, or darker than testa; not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to embryo. 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; partially concealing radicle; with lobes; with lobes touching (auriculate); without 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 to deflexed (slightly); parallel to length of seed to oblique to length of seed (slightly); without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; straight with embryonic axis; centered between cotyledons; less than 1/2 length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Mexico and Central America, And Paraguay and Argentina.

New World; Mexico, Central America, and South America (Paraguay and Aregentina); Argentina.

Generic Notes

The two species, Microlobius foetidus (N.J. von Jacquin) M. Sousa S. & G. Andrade M. and Goldmania paraguensis (G. Bentham) J.P.M. Brenan, have similar seed and fruit characters but divisive distributions. Sousa and Andrade (1992) showed that Goldmania J.N. Rose ex M. Micheli and Microlobius are synonymous, so the older name, Microlobius must be used for this genus. They also synonymized its species so that it is now monotypic. The single species is M. foetidus with two subspecies: M. foetidus subsp. foetidus from Mexico and Central America and M. foetidus subsp. paraguensis (G. Bentham) M. Sousa S. & G. Andrade M. from Paraguay and Argentina. The species count of Sousa and Andrade (1992) is used.