Mimosa widgrenii Harms
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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
471. Mimosa widgrenii Harms, Repert. Spec. Nov. Regni Veg. 18: 233. 1922.—"Brasilien: Minas Geraes (Widgren [anno] 1845."—Holotypus, +B = F Neg. 14451; isotypi, BR! GH! M! S!
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Description
Species Description - Tall, erect or perhaps scrambling herbs, possibly suffrutescent but the lower parts unknown, the coarse, strictly branching, obtusely ribbed reddish homotinous stems at least 7-10 dm and 2.5-4 mm diam., at once armed with irregular files of slender recurved intemodal aculei to 1.5-3 mm and densely hispid with erect tapering yellowish or rufous setae to 1-4 mm, the dorsal rib of lf-stks similarly prickly and hispid but the axis of pinnae and the peduncles hispid only, the small firm, closely imbricate, ventrally dark-olivaceous, dorsally pallid lfts glabrous or almost so facially, thinly setose-ciliate, the ellipsoid or globose capitula solitary and 2-3-nate in a long succession of lf-axils or distally forming a shortly exserted pseudoraceme. Stipules firm erect-incurved, linear or linear-lanceolate 3.5-6.5 x 0.3-0.8 mm, 1-nerved and setose dorsally, persistent through duration of associated lf. Leaf-stalks 2-6.5 cm, the petiole with livid wrinkled pulvinus 6-20 mm, at middle 0.3-0.7 mm diam., the interpinnal segments 3-7 mm, ridged (not sulcate) ventrally; interpinnal spicules 0; pinnae 5-10- jug., subequilong or decrescent proximally, the rachis of longer ones (10-) 12-25 mm, the interfoliolar segments 0.3-0.8 mm; lfts 20-32-jug., subequilong except at very ends of rachis, the first pair 0.2-0.6 mm distant from subulate paraphyllidia 0.2-0.4 mm, the blades oblong or oblong-elliptic obtuse from semicordate base, those at mid-rachis 2.3-3.6 x 0.5-1 mm, 3.6—4.6 times as long as wide, all smooth veinless above, beneath weakly carinate by simple pallid midrib directed obliquely across blade from pulvinule to slightly incurved tip. Peduncles 1-3.5 cm; capitula without filaments 5-10 x 5-6 mm, prior to anthesis moriform, the obtusely 4-carinate fl-buds thinly retrostrigulose between pallid ribs; bracts linear-oblanceolate 1.3-2 x 0.2-0.4 mm, glabrous 1-nerved dorsally, the margins setose-ciliate beyond middle, the cilia to 0.5-1.1 mm; flowers 4-merous 4-androus, all bisexual or a few proximal ones staminate and smaller; calyx paleaceous-pappiform, the setae to 1-1.4 mm, obscurely united through 0.2-0.4 mm into four lobes; corolla turbinate (1.6-)2.2-2.8 mm, the firm 1-ribbed, shallowly concave lobes (0.7-)0.85-l x (0.45-)0.55-l mm; filaments (presumably pink) free to base, exserted ±6 mm; ovary at anthesis glabrous, soon after fertilization thinly setulose. Pods numerous in globose hispid capitula 13-16 mm diam., each sessile and in profile broadly elliptic 4-6 x 3 mm, 2-ovulate 1-2-seeded, the replum ±0.5 mm diam., charged along back and sides with divaricate lustrous golden-brown setae to 3-3.5 mm, the brown papery valves low-colliculate over each seed, thinly yellowish-setulose, when ripe separating entire from each other and from replum but often long retained with seed(s) within the mesh of replar setae; seeds plumply obovoid ±2 x 1.6 mm, the testa fuscous dull.
Distribution and Ecology - In moist campo, apparently local and not recently collected, known only from hill country in the southern most angle of Minas Gerais, Brazil (Caldas; S. Antônio do Jardim; Machado), near 22°S, 46°W.-F1. (?—)III(—?).
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Discussion
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Distribution
Brazil South America| Minas Gerais Brazil South America|