Monographs Details: Mimosa acantholoba (Humb. & Bonpl. ex Willd.) Poir.
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1991. Sensitivae Censitae. A description of the genus Mimosa Linnaeus (Mimosaceae) in the New World. Mem. New York Bot. Gard. 65: 1-835.
Description:Species Description - Amply microphyllidious, potentially arborescent shrubs and bushy trees (1—)2—7 m, armed on most internodes with 1-2 infrastipular and 1 infrapetiolar, stout broad-based recurved aculei and on either dorsal or lateral ribs of some lf-stks with similar but shorter ones (occasional branchlets unarmed), the young stems and lf-axes puberulent and livid-granular, neither setose nor glandular, the foliage fresh-green subconcolorous, the plane thin-textured lfts either glabrous on both faces or puberulent beneath, the globose, ellipsoid, or spicate partial inflorescences axillary to contemporary or hysteranthous lvs, in early anthesis often forming an exserted pseudoraceme but the fruits immersed in lvs. Stipules erect subulate 1-4 x 0.25-0.5 mm, 1-nerved, persistent. Leaves variable in development, the hysteranthous ones (in specimens associated commonly with mature fruit) often shorter and simpler, the lf-stks 4-13(-22) cm, the petiole 6- 25(-35) x 0.5-1.1 mm, the longer interpinnal segments (4—)5—15(—18) mm, the deep ventral sulcus continuous between pinnae (spicules 0); pinnae of primary lvs 7-15(-26)-jug., of some distal lvs only (2-)4-6-jug., randomly decrescent at each end of lf-stk, the rachis of longer ones (1.2—) 1.5—4.2(—5.5) cm, the longer interfoliolar segments 0.5-1.2(-l .4) mm but in broad-lft forms 1.5-3 mm; lfts of longer pinnae (15-) 18-34(-40)- jug., decrescent at each end of rachis, the small first pair 0.3-1.6 mm distant from ascending subulate paraphyllidia 0.2-0.5 mm., the blades linear or linear-elliptic from obtusangulate base, obtuse or deltately apiculate at apex, those near mid-rachis (2-)2.6-7(-8) x (0.6-)0.7-1.8(-2) mm, (3-)3.3-5.4 times as long as wide, all veinless above, beneath 2-nerved from pulvinule, the midrib only a little forwardly displaced, the faint posterior nerve expiring or weakly brochidodrome short of mid-blade. Peduncles either solitary or 2-4(-5) per node, 5-24 mm; capitula or spikes 4-6.5 mm diam. without filaments, the floral axis 1-35 mm, the obtuse fl-buds usually glabrous, rarely with a few minute hairs at tip; bracts 0.5-1 x 0.15-0.25 mm, caducous; flowers sessile or almost so, (4-)5-merous diplostemonous, mostly bisexual; calyx membranous campanulate 0.45-0.9 (in var. eurycarpa to 1.4) mm, glabrous or exceptionally thinly puberulent below the broadly shallowly lobulate rim; corolla whitish, vase-shaped or the lowest ones turbinate, 2.2-3.2 mm, the membranous ovate subacute 1-nerved lobes 0.7-1.3 x 0.6-0.8 mm, at full anthesis usually arched outward; filaments usually white, in S. America sometimes pale pinkish, obscurely monadelphous through not more than 0.3 mm, exserted (3.5-)4—5.5(-6) mm; ovary short-stipitate puberulent. Pods commonly 1, sometimes 2-3 per capitulum or spike, the broadly elliptic indehiscent body 3.5-8 x 1.6-2.3 cm, mostly 4-8-seeded, cuneately contracted at base into a stipe 6-14 mm and more abruptly so at apex into an erect cusp 1-4 mm, the sutures 0.45-0.65 mm diam., the seminiferous one either narrowly winged or with a commonly continuous, sometimes interrupted file of laterally compressed, broad-based, nearly erect aculei to ±1-2.5 mm, the permanently unsegmented valves at first green livid-granular piano-compressed, when ripe becoming stiffly papery or crustaceous and over the seeds discolored and often densely hispid-setose, the cavity continuous; seeds on long capillary funicle, crowded near middle of valves transverse to the pod’s long axis, lenticular 4.6-5.2 x 3-3.7 mm, the testa castaneous lustrous.

Distribution and Ecology - A polymorphic and pluriracial species of seasonally dry scrub-woodlands on the Pacific lowlands of tropical N. and n. S. America, extending discontinuously from Sinaloa, Mexico to n.-w. Peru, in centr. America e. to the Caribbean slope in Guatemala and Honduras; only var. acantholoba in S. America.



Distribution:Guatemala Central America| Honduras Central America| Mexico North America| Sinaloa Mexico North America| Peru South America|