Mimosa ramulosa Benth.
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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
374. Mimosa ramulosa Bentham, J. Bot. (Hooker) 4: 385. 1841.-"Brazil, Sello.", the data expanded by Bentham, 1875: 409 to: "Brazil, southern provinces and adjoining parts of the Argentine Republic.", and further, in Martius, Fl. bras. 15(2): 347. 1876 to:
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Synonyms
Mimosa ciliata Spreng.
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Description
Species Description - Repeatedly, stiffly, often flexuously branched microphyllous shrubs attaining 2(-?) m, erratically armed on internodes, especially of terminal flowering branches, with distantly displaced infrapetiolar, widely ascending or horizontal, straight broad-based aculei 2-6 mm, the stems and peduncles densely strigose with retrorsely appressed, basally calcarate and obcompressed setae to 0.65-1.5 mm, the small subsessile olivaceous lvs either shorter or a little longer than internodes, the firm concolorous, callous-marginate, imbricate lfts facially glabrous or only microscopically puberulent, commonly minutely setulose-ciliolate, the small and numerous globose capitula solitary or rarely geminate in a long succession of lf-axils, elevated on a peduncle ± as long as or surpassing the associated lf. Stipules firm erect, narrowly triangular or lanceolate 1.5-3 x 0.55-1 mm, 2-5-nerved dorsally, glabrous or almost so, persistent. Leaf-stalks including (or consisting of) pulvinus 0.5-1.5(-2.5) mm; spicule 0; pinnae 1-jug., the antrorsely strigose rachis 2.5-13 mm, the longer interfoliolar segments 0.3-0.6 mm; lfts 6-15(-17)-jug., decrescent at each end of rachis, the first pair 0.1-0.2 mm distant from minute subulate or conic paraphyllidia, the blades lance-elliptic obtuse or subapiculate, those near mid-rachis (1.3-)2-4 x 0.4-0.9 mm, ±2.4-4.4 times as long as wide, all veinless above, beneath 2-nerved from pulvinule, the simple midrib excentric proximally but subcentric distally, the posterior nerve weaker, expiring near or short of mid-blade. Peduncles 6-12 mm; capitula without filaments 3-4 mm diam., prior to anthesis moriform, the obtusely 4-angulate fl- buds minutely puberulent; bracts ovate-cymbiform acute 0.4-0.7 x 0.25-0.5 mm, 1-nerved, dorsally puberulent, persistent; flowers 4-merous 4-androus, many lower ones staminate; calyx a subtruncate membranous collar 0.1-0.15 mm; corolla turbinate 1.5-1.9 mm, the ovate, weakly 1-nerved lobes 0.6-0.9 x 0.5-0.7 mm; filaments pink or lilac, free to base, exserted 1-1.7 mm. Pods not seen fully mature, when young linear in profile, densely subappressed-setose.
Distribution and Ecology - In stony campo and at edge of thickets at low elevations, apparently confined to the Atlantic slope in e. Rio Grande do Sul, Brazil and adj. Uruguay.-Fl. IV-VI(-?).
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Discussion
In stature, armature and leaflet-number M. ramulosa closely resembles M. sprengelii, but it has longer peduncles, shorter stamens, and appressed-strigose fruits probably articulate when ripe, not hispidly setose, burlike and valvately dehiscent. Its small pedunculate capitula are almost those of M. parvipinna, but it is a taller shrub with prickly branchlets and fewer leaflets (in larger pinnae 6—15(—17), not 12-30 pairs). The paucity of collections presently available precludes a firm taxonomic opinion of this group of species.
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Distribution
Brazil South America| Rio Grande do Sul Brazil South America| Uruguay South America|