Mimosa pogonoclada 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
416. Mimosa pogonoclada Bentham, Trans. Linn. Soc. London 30: 399 (loc. ‘Parana’ excepto). 1875 & in Martius, Fl. bras. 15(2): 321, descr. ampliat. 1876. —"Habitat in provincia S. Paulo ad Uberaba: Regnell III n. 499; ad Cuiabá et Camapuam prov. Matto Gro
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Description
Species Description - Unarmed perennial herb with humistrate, randomly branched stems to 7 dm or more, these with lf-axes and peduncles densely coarsely setose throughout with subvertical, almost straight tapering setae to 2-3.5(-4) mm, the olivaceous brunnescent lvs sub-bicolored, the lfts glabrous above, beneath thinly strigulose-setulose and a little paler, immarginate but hispid-ciliate, the globose or plumply ellipsoid capitula solitary and paired in a long succession of lf-axils on peduncle as long as or longer than the associated lf. Stipules erect firm lanceolate 4-5 x 1-1.5 mm, puberulent on both faces, setose-ciliate, persistent. Leafstalks (1.5-)2-3.5 cm, the proper petiole including pulvinus 7-15 x 0.5-0.8 mm, the longer interpinnal segments 5-7 mm, the shallow ventral groove bridged between pinnae but spicules 0; pinnae 4-jug., a little decrescent distally, the axis of longer ones 14-30 mm, the interfoliolar segments 1.2-2 mm; lfts of longer pinnae 10-17- jug., subequilong, the first pair less than 1 mm distant from lanceolate paraphyllidia 0.6-1 mm, the blades obliquely oblong or half-ovate from obtusangulate base, abruptly deltate-apiculate mucronulate, the larger ones 4.5-6.5 x 1.4-2 mm, 2.5-3.5 times as long as wide, all veinless and dull above, beneath sharply 5-6-nerved from pulvinule, the simple midrib displaced to divide blade ±1:2-2.5, the one anterior primary nerve weak submarginal or lacking, the inner posterior one produced nearly to blade apex, the outer posterior ones progressively shorter, the venation pallid and sharply defined. Peduncles strongly compressed 4-5.5 cm; capitula without filaments 6-7 mm diam., prior to anthesis moriform, the obtusely 4-angulate fl-buds microscopically puberulent at tip; receptacle densely setose; bracts linear-oblanceolate 1.7-2 x 0.3-0.5 mm, dorsally glabrous and carinate, setose-ciliate distally; flowers 4-merous 4-androus; calyx paleaceous 1.8-2.6 mm, the tube 0.5-0.8 mm, the four scarious lobes decompound ± half-way into tapering setae; corolla narrowly funnelform 4-ribbed 2.5-3.1 mm, the firm ovate cymbiform lobes 0.5-0.9 mm; filaments monadelphous through 1-1.5 mm, exserted to 7 mm. Pods (Krapovickas 33074, NY) to 10 per capitulum, sessile, in profile linear-oblong to 15 x 5 mm and 2-3-seeded, the undulately constricted replum ±0.3 mm diam., hispid on back and sides with tapering smooth setae to 3 mm, the papery valves brown glabrous, breaking up into free-falling articles to ± 5 mm long.
Distribution and Ecology - In campo near 300-400 m, apparently localized in the Triângulo of w. Minas Gerais, known precisely only from near Uberaba and Frutal (±20°S, 48—49°W).—Fl. XII-II.
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Discussion
Mimosa pogonoclada, which is known to me from only one collection besides the type, can be visualized as a small-leaved, unarmed version of M. hirsutissima, which it closely resembles in leaflet-venation and floral morphology. Its leaves are rather smaller than those of M. hirsutissima, and composed of up to four pairs of pinnae which are not crowded near tip of leaf-stalk, thereby imparting a certain individuality of facies. Judgment as to its independent specific status must be suspended until more can be learned of its habits and potential variability. In general aspect it simulates M. distans var. elongata, but its corolla-lobes lack the silvery retrorse indumentum characteristic of subser. Reptantes.
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Distribution
Brazil South America| Minas Gerais Brazil South America|