Monographs Details: Mimosa cisparanensis 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.
Family:Mimosaceae
Synonyms:Mimosa neptunioides Harms, Mimosa occidentalis Britton & Rose
Description:Species Description - Erect subshrubs ±1 m, randomly armed on some internodes with 1-2 erect straight weak aculei 1.5-2.5 mm, the simple terete stems, lf-axes and peduncles hispid with suberect tapering yellowish or tawny setae to 2-4 mm and not more than 0.1 mm diam. at base, and in addition finely gray-puberulent, eglandular, the olivaceous, conspicuously stipulate lvs subconcolorous, the lfts glabrous facially, setose-ciliate, the dense ellipsoid capitula single in a long succession of lf-axils, at anthesis shortly emersed from coevally expanding foliage but quickly lateral. Stipules amplexicaul, ovate from broad subcordate base, deltately apiculate, 7-8 x 4-5 mm, thinly setose dorsally, glabrous within, the brown blade striately ±40-50-nerved, setose-ciliate, persistent. Leaf-stalks 1-2 cm, the petiole reduced to the pulvinus, the longer interpinnal segments 5-8 mm, the ventral sulcus interrupted between pinna-pairs by a laminulate spicule 2-2.5 mm, the terminal appendage of lf-stk likewise laminulate and ±5-6.5 x 1.5-2 mm; pinnae 2-4-jug., strongly accrescent distally, the proximal pair ± 1 cm and the distal pair 3-4 cm, the interfoliolar segments 0.6-1.5 mm; lfts of distal pinnae 17-24-jug., decrescent at each end of rachis, the first pair less than 1 mm distant from minute paraphyllidia, the blades narrowly oblong obtuse from bluntly auriculate base, those at mid-rachis ±5.5-7 x 1.4-1.8 mm and ±4 times as long as wide, all 6-8-nerved from pulvinule, the subcentric midrib 2-3-branched on each side from below middle, the inner posterior and inner anterior nerves produced nearly to blade apex, the rest progressively shorter, the venation immersed above, pallid and prominulous beneath, the marginal cilia to 0.8-1.5 mm. Peduncles 1.5-2 cm; capitula without filaments 12-15 x 6.5-7.5 mm, prior to anthesis conelike, the bracts wholly concealing the fl-buds; bracts resembling stipules in texture and striate venation, elliptic-obovate ±3x2 mm, the margin erose and setose-ciliate; flowers 4-merous 8-androus; calyx shallowly campanulate 0.5-0.6 mm, externally glabrous, the undulately 4-lobed rim weakly ciliolate; corolla narrowly turbinate ±3 mm, the triangular lobes ±0.9 x 0.9 mm, thinly setose dorsally, the slender midrib faintly branched; filaments pink, monadelphous through ± 1 mm, exserted 8 mm. Pods numerous per capitulum, sessile, in profile narrowly oblanceolate 13-15 x 6 mm, mostly 3-seeded, the nearly straight replum 0.5-0.6 mm wide, the papery reddish-brown valves elevated over each seed, the replum and valves alike densely hispid-comose overall with slender smooth lustrous, incurved-ascending setae to 4-6.5 mm, the replum at maturity splitting at apex and the valves breaking up into free-falling, individually dehiscent articles 3-3.5 mm long; seeds obliquely descending, compressed-obovoid ±3 x 2.2 mm, the testa lustrous black.

Distribution and Ecology - In unknown habitat, but to be expected in open places near or below 200 m, known only from the type-locality in the valley of rio Cuiabá near 15°S, 56°30'Win s.-centr. Mato Grosso, Brazil.— Fl. ±XII-II.

Discussion:

Although known as yet from only one collection, M. cisparanensis appears specifically distinct from the obviously related M. neptunioides in stiffly erect, not trailing stems, weak scattered prickles, reduction of the true petioles to the leaf-pulvinus (the first pair of pinnae consequently arising as it were directly next the stem), and particularly in the broad pod comosely hispid with much longer setae. In pod and armament it resembles distantly allopatric M. occidentalis, but this differs fundamentally in number of pinna-pairs.

Distribution:Brazil South America| Mato Grosso Brazil South America|