Monographs Details: Mimosa urticaria Barneby
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 urticaria Barneby
Synonyms:Mimosa bathyrrhena Barneby
Description:Species Description - Amply leafy unarmed shrubs ± 3 m, the hornotinous stems, lf-stks and axes of pyramidally branched inflorescence tomentellous with erect plumose setulae to 0.4(-0.5) mm, the thin-textured lvs (dry) dull brownish-olivaceous concolorous, the lfts finely stellate on both faces, the plumply ellipsoid capitula exserted from foliage but most peduncles subtended by hysteranthous lvs. Stipules erect, linear-ligulate or -attenuate (5-)6-8 x 1 mm, tomentellous on both faces, 1-nerved dorsally, subpersistent. Leaf-stalks 2-3 cm, 0.5-0.7 mm diam.; pinnae 1-jug., the rachis (4.5-)5-7 cm, the interfoliolar segments 3-4 mm; lfts 14-19-jug., subequilong, the first pair 1.2-2 mm distant from subulate paraphyllidia 0.6-1.5 mm, the blades narrowly oblong from obtusangulate base, deltate-apiculate, the larger ones 9.5-14.5 x 2.6-4 mm, 3.2-3.8 times as long as wide, all veinless above, beneath finely 4-nerved from pulvinule, the moderately displaced midrib prominulous proximally, faint distally, the inner posterior nerve expiring short of mid-blade, the one anterior and the outer posterior nerve very short or subobsolescent. Peduncles solitary and 2-3-nate, 6-20 mm; capitula without filaments 7-10 x 5-5.5 mm, prior to anthesis moriform; bracts sublinear 1.1-1.5 x 0.15 mm, puberulent distally, caducous; flowers 4-merous 4-androus, the lower ones staminate and a little smaller than distal ones; calyx reduced to a shallow membranous collar ±0.15 mm, the rim obscurely lobulate and ciliolate; corolla narrowly turbinate 2.1-2.5 mm, densely creamy-stellate overall, the cymbiform, scarcely thickened lobes 0.6-0.7 x 0.6-0.7 mm; filaments yellow, at base monadelphous through ±0.7 mm, without intervening staminodia, exserted 3-4 mm; ovary puberulent; pod unknown.

Distribution and Ecology - In capoeira at unrecorded elevation, known only from the municipio of Ortigueira (bairros dos Machados and dos França), near 24°15'S, 51°W in centr. Paraná.—Fl. XII-I(-?).

Discussion:

Mimosa urticaria (the epithet alludes to the type-locality) appears well characterized by conjugate pinnae borne on a relatively long petiole, expansive thin-textured concolorous leaflets thinly stellate on each face, corollas stellate from base upward, and lack of staminodia between the monadelphous fertile stamens. In general aspect it recalls M. bathyrrhena, also endemic (so far as known) to upland ParanĂ¡, but this is clearly different in bijugate pinnae, longer pinnae and floral bracts, and staminodia between the filaments. The common M. pilulifera var. pseudincana has one pair of pinnae like M. urticaria, but petioles only 1-4 mm long and strongly bicolored leaflets scarcely half as big.

Distribution:Brazil South America| ParanĂ¡ Brazil South America|

Narratives:Mimosa urticaria
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