Monographs Details: Mimosa josephina Barneby
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.
Synonyms:Mimosa rojasii Hassl.
Description:Species Description - Erect unarmed subshrub ± 1 m with stiff virgate, equably leafy stem branched distally into a thyrsiform, proximally leafy panicle of plumply ellipsoid capitula, viscid-puberulent almost throughout with short white hairs and gland-tipped setulae to 0.1-0.3 mm, esetose, only the faces of some of the plane thick-textured, dorsally venulose lfts glabrous or almost so. Stipules firm erect triangular or lanceolate 3-7 x 1.3-3 mm, striately 8-15-nerved, persistent. Leaf-stalks 4-10.5 mm, the petiole including hard pulvinus ±9-20 x 0.8-1.6 mm, the interpinnal segments to 8-13 mm, the open shallow ventral groove bridged between pinna-pairs but spicules 0; pinnae 5-8-jug., decrescent proximally, the rachis of longer ones 2-7 cm, the interfoliolar segments to 1-2.5 mm; lfts of longer pinnae 22-30-jug., subequilong except at very ends of rachis, the first pair 1-1.7 mm distant from oblanceolate paraphyllidia 0.6-1 mm, the blades oblong from obtusangulate base, obtusely deltate at apex, those near mid-rachis 5-9 x 1.5-2.8 mm, 3-3.5 times as long as wide, all nearly veinless above, beneath coarsely prominulously 4-nerved from pulvinule, the midrib subcentric beyond mid-blade and pinnately 5-7-branched on each side, the anterior and inner posterior nerves narrowly intramarginal, produced almost to blade apex and anastomosing with the secondary branches of midrib, the outer posterior nerve very short. Peduncles 2-3-nate, 3-4 cm; capitula without filaments 10-12 x 8-9 mm, prior to anthesis moriform, the narrowly clavate receptacle 7-9 mm; bracts oblanceolate or obovate 1.4-2 x 0.6-1 mm, subglumaceous 9-13-nerved, nidulating the obovoid obtuse stipitate-glandular fl-buds, deciduous at anthesis; flowers 4-merous 8-androus, most (perhaps all) bisexual; calyx sessile campanulate 0.7-0.9 mm, glabrous externally, the subtruncate rim minutely gland-fimbriolate; corolla turbinate-vase-shaped 4 mm, the ovate 3-nerved lobes ±1.5 x 1.3 mm, the lobe-tips thinly puberulent and stipitate-glandular; filaments lilac-pink, monadelphous ± 1 mm around stipe and base of ovary, exserted 8-9.5 mm; ovary viscid-puberulent. Pods 1-3 per capitulum, in profile undulately linear straight 65-90 x 6-7 mm, 9-12-seeded, at base attenuate into a stipe 2-4.5 mm, shortly cuspidulate at apex, the shallowly constricted replum 0.6-1 mm wide, the papery valves low-bullate over each seed, the replum and valves alike thinly minutely viscid-puberulent overall, when ripe breaking into free-falling, individually dehiscent elliptic articles 6-8 mm long; seeds lentiform 3.8-4.3 x ±3.3 mm, the testa dark brown, smooth, highly glossy.
Distribution and Ecology - In dry sandy ground near 300 m, known only from the type-locality near S. Jose de Chiquitos, at 17°50'S, 60°45'W in Sta. Cruz, Bolivia.-Fl. (?-)XII-I.
Mimosa josephina has many features in common with Paraguayan M. rojasii: striately nerved stipules and floral bracts; partly glandular indumentum; leaflets coarsely venulose dorsally in a characteristic design; and plumply ellipsoid capitula. The pair seem surely allied, but differ significantly in stature and pubescence, in venation of corolla-lobes, and in length of pod correlated with ovule- and seed-number. These differences, set out in the key to ser. Rojasianae and in the foregoing diagnosis of M. josephinae, are strengthened by a gap of some 700 km between their known ranges, to the east and west of the Paraguai valley respectively. The less closely related but almost or actually sympatric M. neptunioides differs from M. josephina in diffuse hispid-hirsute but eglandular stems, stipules at once larger and more elaborately striate-venulose, few (2-4, not 5-8) pairs of pinnae in larger leaves, and enlarged floral bracts that conceal the flower-buds prior to anthesis.
Distribution:Bolivia South America
| Santa Cruz Bolivia South America