Mimosa obstrigosa Burkart
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Authors
Rupert C. Barneby
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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.
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Family
Mimosaceae
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Scientific Name
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Type
373. Mimosa obstrigosa Burkart, Darwiniana 7: 231, fig. 4, lam. 1. 1946.-"Argentina. Misiones: . . . Santa Ana, Rodríguez 520 [fl] . . . Apóstoles, Burkart 14291 [fr]. . . .’’-Syntypi, SI (not seen); isosyntypus, Burkart 14291, GH! RB! M. obstrigosa sensu
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Description
Species Description - Intricately freely branched shrubs attaining 2.5 m, the stiff brown homotinous stems randomly armed with stout subhorizontal or widely ascending aculei 2-6(-7) mm and together with peduncles strigose with retrorsely appressed, basally spurred paleaceous setae to 1-2.5 mm, the back of lf-stks similarly but antrorsely strigose and minutely puberulent, the imbricate lfts glabrous on both faces or finely puberulent beneath, slenderly pallid-marginate and finely setulose-ciliolate, the numerous globose capitula solitary pedunculate in a series of lf-axils along all new branchlets. Stipules firm erect, triangular or lance-acuminate 2-5 x 0.6-1 mm, prominently 3-5-nerved, glabrous or less often puberulent externally, tardily deciduous. Leaf-stalks including pulvinus 1-2.5 mm, spicule 0; pinnae 1-jug., the rachis 12-35 mm, the longer interfoliolar segments 0.2-0.9 mm; lfts (16-) 18-28 (t. Burkart to 36)-jug., the first pair less than 0.5 mm distant from subulate paraphyllidia to 0.3 mm, the blades linear from obtusangulate or shallowly auriculate base, apiculate at tip, straight or subfalcate, those near mid-rachis 3.5-6 x 0.65-1.1 mm; ±5-6 times as long as wide, all 2(-3)-nerved from pulvinule, the simple midrib displaced to divide blade ± 1:2-3, the inner (or only) posterior nerve expiring well beyond mid-blade, the outer one, when present, very short or rudimentary. Peduncles 7-19(-23) mm; capitula without filaments 5-7 mm diam., prior to anthesis moriform, the obtuse fl-buds gray-puberulent; bracts linear, distally attenuate and incurved, 1-2 mm, 1 -nerved, pilosulous dorsally, persistent; flowers 4-merous 4-androus, some lower ones staminate; calyx campanulate ±0.4 mm glabrous, at base contracted into a pedicel ±0.1 mm, the rim minutely asymmetrically denticulate; corolla subtubular slightly widened distally, 2.6-3.1 mm, the membranous, shallowly concave, faintly 1-nerved lobes 0.7-1 x 0.6 mm; filaments pink, obscurely united at very base, exserted 4.5-5.5 mm. Pods 2-5 per capitulum, sessile, in profile linear-oblong, straight or slightly decurved, (8—)11—22 x 3.5-5.5 mm, (2-)3-6-seeded, the straight or shallowly constricted replum ±0.4 mm wide, the valves low-convex over seeds, the replum and valves alike densely strigose with forwardly appressed, basally dilated pallid setae to 1-1.5 mm, when ripe breaking up into individually indehiscent articles 2.3-4 mm long; seeds obliquely basipetal, in broad profile obovate ± 3-3.5 x 2-2.5 mm, the smooth testa fuscous brown or black.
Distribution and Ecology - In wet campo and at thicket margins, below 200 m, locally plentiful in the lower Paraná valley in s.-w. Misiones (deptos. Sta. Ana, S. Ignacio, Posadas) and adj. Corrientes (Loreto), Argentina, to be expected across the river in s. Paraguay.—Fl. VI-IX, occasionally later.— Espinillo.
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Discussion
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Distribution
Brazil South America| Paraná Brazil South America| Argentina South America| Misiones Argentina South America| Corrientes Argentina South America| Loreto Peru South America| Paraguay South America|