Mimosa falcipinna Benth.

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

Scientific Name

Mimosa falcipinna Benth.

Type

461. Mimosa falcipinna Bentham, J. Bot. (Hooker) 4: 371. 1841.-"Brazil, Pohl.", the locality expanded in Martius, Fl. bras. 15(2): 325. 1876 to: "in provincia Goyaz ad Serra dos Christaës."-Holotypus, Pohl d.1468 = 719, K (hb. Hook.)! = NY Neg. 1806; isot

Description

Species Description - Functionally herbaceous subshrub from xylopodium and a carrot-shaped woody root, the simple terete stems flexuously procumbent or humifuse (l-)2-4.5(-6) dm, these together with lf-axes, lft-margins and peduncles hispid with erect, tapering or flagelliform, commonly sordid or rufescent setae to 3-5 mm mixed with minute puberulence and scattered discolored granular trichomes, the firm plane, dorsally thickly pallid-marginate lfts olivaceous glabrous above, beneath pallid or subglaucous and often thinly setose, the plumply ovoid or subglobose capitula solitary or (distally) 2-3-nate in all axils upward from near mid-stem on subvertical peduncle much longer than subtending lf-stk but either longer or shorter than the whole lf. Stipules erect firm, lanceolate (4-)5-10 x 0.7-1.7 mm, coarsely (3-)5-nerved, either glabrous or setose dorsally, setose-ciliate, persistent. Leafstalks 1.5-4.5 cm (those near mid-stem often longest), at middle (0.4-)0.5-0.9 mm diam., rounded dorsally, coarsely 2-ridged ventrally, espiculate; pinnae 1-jug., their straight or gently retro-arcuate rachis 3-7(-8) cm, the interfoliolar segments 2-4.5 mm; lfts 14-23- (of some depauperate early lvs only 9-15-, no further described)-jug., gradually decrescent upward, abruptly so proximally, the first, often unequal pair 1-2.5 mm distant from lance-subulate paraphyllidia (0.7-)l-2 mm, all in outline very obliquely lanceolate or lance-oblong from broadly obtusangulate base, obtuse apiculate, those near mid-rachis (9.5-) 10-15.5 x 2.5-4.3(—4.5) mm, (2.9-)3-4.5(-4.8) times as long as wide, all smooth above, beneath (3-)4-5-nervedfrom broad short pulvinule, the thick pallid midrib strongly displaced at base of blade but subcentric toward apex, the posterior nerves progressively weaker and shorter outward, the innermost one confluent with the pallid margin near or beyond mid-blade, the outer ones much shorter. Peduncles laterally compressed 3-9 cm; capitula without filaments or bracteal setae 6- 7.5(-8) mm diam., prior to anthesis submoriform but usually hispid with shortly emergent setae; bracts linear or linear-oblanceolate 1.3-3 x 0.3-0.5 mm, prominently pallid-keeled, charged on each margin above middle with 2-4 widely ascending setae to 1-2 mm, persistent; flowers 4-merous 4-androus, some or many proximal ones staminate; calyx a membranous collar 0.1-0.15 mm tall, the undulate margin glabrous or with a few minute setulae not over 0.15 mm; corolla narrowly vase-shaped 2.4-3.2 mm, the concave lobes (0.5-)0.6-0.8 x 0.5-0.7 mm, dorsally pallid-carinate, on each side of keel retrorsely strigulose; filaments pink, weakly monadelphous about base of glabrous ovary, exserted 6-8 mm. Pods commonly 2-10 per capitulum, cryptically stipitate, the body in profile undulately narrow-oblong straight 14-18 x 4-4.5 mm, 3-4-seeded, the constricted replum 0.4-0.5 mm diam., contracted at apex into a short subulate cusp, densely or thinly hispidulous with erect or subretrorse, basally thickened setae 0.5-1 mm, the papery brown valves either glabrous or remotely retro-strigulose, breaking up when ripe into biconvex, free-falling articles 4-5 mm long; seeds (Irwin 26093, NY) plumply lentiform ±3.5 x 2.7 mm, the smooth testa reddish-brown sublustrous.

Distribution and Ecology - In campo sujo and open cerrado, on crystalline rock-sands and laterite, 700-1050 m, resistant to fire, locally plentiful on upper rios Corumbá, S. Bartolomeu and S. Marcos in s.-e. Goiás and Distrito Federal, thence extending e. across Sa. da Tiririca just into adj. Minas Gerais, Brazil.— Fl. late X-III.

Discussion

Mimosa falcipinna is closely related to M. distans var. distans, and precariously distinguished at the specific level by weak, humifuse stems and by the indumentum of extremely long sub vertical setae of stems, leaf-stalks and peduncles.

Distribution

Brazil South America| Minas Gerais Brazil South America| Distrito Federal Brazil South America| Goiás Brazil South America|