Mimosa flagellaris 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
338. Mimosa flagellaris Bentham, J. Bot. (Hooker) 4:372. 1841.- "Near Porto Alegre [Rio Grande do Sul, Brazil], Tweedie; Brazil, Sello."—Lectotypus, Tweedie 69, K(hb. Hook., excluding plant at mid-sheet, which = M. dolens var. pubescens)\ = NY Neg. 1804;
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Synonyms
Mimosa dolens var. pubescens (Benth.) Barneby, Mimosa flagellaris var. hirsuta Benth.
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Description
Species Description - Unarmed macrophyllidious, functionally herbaceous subshrubs from stout woody root and shortly branched subterranean caudex, the flexuously humifuse stems 1—5(—6) dm, at least when young pilose, like lf-stks and subvertically erect peduncles, with fine sordid or yellowish setae to 2-4 mm often mixed with minute gray puberulence, the plane chartaceous, subconcolorously olivaceous (brunnescent), opaque or lustrous, dorsally venulose lfts either glabrous on both faces, or villosulous beneath either overall or only toward margin, or villosulous on both faces and then sometimes in addition finely sparsely setose-strigose beneath, the solitary or exceptionally geminate peduncles much longer than the subtending lf. Stipules erect firm, lanceolate or narrowly ovate, obtuse or subacute, coarsely 3-6-nerved, dorsally either glabrous or puberulent, pectinately ciliate, persistent. Leaf-stalks 5-20 (-25) x 0.4-0.75 mm, the shallow open groove terminating in a slender, straight or often forwardly curved, glabrous or puberulent spicule 0.6-3 mm, this sometimes concealed between pinna-pulvini; pinnae 1-jug., the rachis (1.5—)2— 4.5(-5) cm, the interfoliolar segments (4.5—)5—11 mm; lfts commonly (3-)4-6-, locally 5-8-jug., decrescent proximally, either the distal or the penultimate pair longest, the very unequal first pair 1-4.5 mm distant from subulate 1-nerved paraphyllidia 0.7-2 mm, the blades obliquely obovate or less often broadly lance-elliptic from amply semicordate base, either broadly obtuse apiculate or deltately subacute, the larger ones (10-) 11.5-24(-28) x (5.5—)6—13.5 mm, 1.6-2.4 (-3) times as long as wide, all beneath coarsely (4-)5-6(-7)-nerved from pulvinule, the midrib displaced to divide blade ±1:2, upward from near middle 3-6-branched on each side, the inner anterior and posterior nerves produced to or much beyond mid-blade, the outer ones shorter, the posterior ones branched on their outer side, all secondary nervules looped within the discontinuously or subcontinuously setose-ciliate margin, the marginal setae 0.1-0.2 mm diam.; a faint tertiary venulation often perceptible. Peduncles (5—)6—14 cm; capitula without filaments 7-8 mm diam., as long or a little longer, prior to anthesis hispidly conelike; bracts elliptic-oblong (1.8—)2—3.5 x 0.5-0.9 mm, largely scarious, 1-nerved, dorsally either glabrous or puberulent, pectinately ciliate; flowers 4-merous, mostly bisexual and 4-androus, but some proximal ones staminate and some of these at times 8-androus; calyx membranous 0.2-0.55 mm, either symmetrically or asymmetrically campanulate, sometimes reduced to a narrow collar, the rim entire or minutely 4-denticulate, usually glabrous, sometimes randomly minutely ciliolate; corolla funnelform 2.9-3.4 mm, the membranous ovate, shallowly concave 1 -nerved lobes 0.9-1.1 x 0.5-0.75 mm; filaments lilac-pink or violet, free to base, exserted 5.5-7.5 mm. Pods usually 10-30 or more per capitulum, sessile, in profile undulately linear-oblong 9-24 x 4-4.5 mm, (2-)3-5- seeded, the shallowly constricted replum 0.3-0.5 mm diam., hispid along back and sides with crowded or well-spaced divaricate-ascending setae to 1.5-2.5 mm, the papery, glabrous or densely puberulent but esetose valves colliculate over each seed, breaking up when ripe into free-falling indehiscent articles 3—4.5 mm long; seeds rhombic-lentiform ±2.6-3.3 mm in broad diam., the smooth testa either fuscous or yellowish-fawn.
Distribution and Ecology - In moist campo, from near sea-level to ± 300 m in Paraguay, locally plentiful in Argentina e. of río Paraná (Corrientes and Entre Ríos) and n.-w. Uruguay, extending weakly n. into s. Paraguay (near 26°S), and perhaps disjunctly e. to the Atlantic coastal plain in e. Rio Grande do Sul, Brazil.—Fl. X-IV.
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Discussion
Mimosa flagellaris is distinctive among humifuse extratropical kindred because of ample veiny leaflets and spiculate leaf-stalks. The latter are comeously thickened at base, immediately above the pulvinus, and in this feature recall the sympatric M. nuda, which has leaflets similar in size and venation, but reduced to one and a half pairs per pinna. The pubescence of the stems and of the corolla lobes is variable, but no correlation with dispersal has been made out. In the sample studied, the leaflets appear to be more numerous by one or two pairs in Atlantic Rio Grande do Sul, but the difference is not a decisive one. A specimen from Paraguay (Villa Rica, Balansa 1469, G), egregious for large leaves, shows these dimensions in excess of the figures given in the foregoing description: leaf-stalks attaining 3 cm; pinna-rachises 4.5-8 cm; leaflets 9-11 pairs. It remains to be shown whether this is a casual variant or is genetically determined. The specimen was annotated, apparently by Chodat & Hassler, as a variety (unpublished) of M. procurrens (l.c., of M. caaguazuensis of this account), from which it differs, inter alia, in constantly conjugate pinnae and rudimentary calyx.
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Distribution
Brazil South America| Uruguay South America| Paraguay South America| Argentina South America|