Monographs Details: Mimosa montis-carasae 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 pogocephala Benth.
Description:Species Description - Erect unarmed shrubs 1-2 m with blackish defoliate trunks 3-4 mm diam. paniculately branched distally, the densely leafy homotinous branchlets hispid with stiff ascending, tapering but not flagelliform setae to 0.8-1.5 mm, the mature foliage dark green (brunnescent when dry), the lfts either glabrous on both faces, or glabrous above and thinly setose dorsally, or subappressed-setose on both faces, discontinuously setose-ciliate, the peduncles at least in fruit axillary to a few distal lvs, the pods not or scarcely exserted from foliage. Stipules slenderly lance-acuminate 3-7 x 0.3-0.6 mm, dorsally setulose, deciduous with associated lf. Leaf-stalks including hard pulvinus 1.5-4 mm; pinnae 1-jug., the rachis of each 2-5.5 cm, the interfoliolar segments (2-)2.5-5.5 mm; lfts of longer pinnae 8-11-jug., little graduated in length, the first pair 1-2 mm distant from subulate paraphyllidia 0.8-2 mm, the blades broad-linear, narrowly lance-oblong or oblong-obovate from semicordate base, acute or apiculate, the larger ones (5.5-)8-14 x (2-)2.6-4 mm, 2.7-3.6 times as long as wide, the dorsal face 4-nerved from pulvinule, the midrib and 1 posterior nerve alone prominent, the midrib displaced to divide blade ±1:2. Peduncles solitary or rarely geminate 2—2.5 cm; capitula not seen at anthesis but apparently subglobose and without filaments ±7 mm diam.; bracts linear-oblanceolate 1.5-1.8 x 0.3 mm, glabrous dorsally, setulose-ciliolate beyond middle; flowers 4-merous 4-androus; calyx shallowly openly campanulate 0.2 mm, the undulate rim either glabrous or microscopically puberulent; corolla 2.5-2.8 mm, the submembranous concave lobes ± 1 x 0.6 mm, externally densely gray-puberulent on either side of glabrous keel; filaments free to base, not seen entire. Pods ±3-10 per capitulum, sessile, in profile oblong-elliptic or elliptic- obovate(7-)10-18 x 5.5-7 mm, (l-)2-4-seeded, in structure, texture and dehiscence like that of M. pogocephala but the replum and valves alike only thinly hispid with tapering curved setae to (1-) 1.5-4 mm and distant from one another by spaces much wider than their basal diameter, the minutely puberulent face of valves not concealed by vesture.

Distribution and Ecology - In rock crevices and humus-filled depressions of sandstone caprock, 1500-1900 m, known only from the upper slopes and summit of Sa. do Caraça in centr. Minas Gerais, Brazil.—Fl. ±X-XI; fr. XII-I.

Discussion:

This appears to be a specialized derivative of the M. pogocephala complex endemic to the heights of Sa. do Cara├ža, where it was first discovered by Peter Claussen (212, BM!). From the rather polymorphic M. pogocephala it differs in hispid, not lanate indumentum of young stems, leaflets variably glabrate or appressed-setose, smaller pinnae and fewer leaflets (as given in the diagnosis) and thinly hispid, not densely setose and bur-like pod.

Distribution:Brazil South America| Minas Gerais Brazil South America|