Monographs Details: Mimosa cuzcoana J.F.Macbr.
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
Description:Species Description - Shrubby or very likely sarmentose but of unknown potential stature, armed on subterete internodes and on back of all lf-axes with open files of broad-based subrecurved, stramineous brown- tipped aculei 1-3 mm, glabrous except for residually puberulent lf-axes and discontinuously appressed-setose lft-margins, the lfts deep green, a little paler beneath, the subglobose capitula mostly 2-3 together in lf-axils and immersed in foliage, or some distal ones in a shortly exserted efoliate pseudoraceme. Stipules firm erect-incurved, narrowly lanceolate 2.5-5 x 0.4-1 mm, coarsely 1-nerved, persistent. Leaf-stalks 0.8-3 cm, at middle 0.6-1.5 mm diam., the ventral groove bridged at apex and charged with a small ascending spicule; pinnae 1-jug., the rachis 3.5-10 cm, charged behind each lft with an appressed setule, the interfoliolar segments 2.5-6 mm; lfts 9-15-jug., a little decrescent at each end of rachis, the unequal first pair 1.5-3 mm distant from subulate paraphyllidia 0.8-1.5 mm, the blades lance-oblong from obtusangulate base, abruptly deltate-acuminulate, those near mid-rachis 12-18 x 3-5.5 mm, 3.3-4 times as long as wide, all 4-5-nerved from pulvinule, the moderately displaced midrib pinnately 3-6-branched on each side, the inner posterior nerve brochidodrome near or beyond mid-blade, the venation faintly discolored but immersed on upper face, sharply prominulous beneath, the marginal setae 0.1-0.15 mm diam., free for ±0.5 mm. Peduncles 12-18 mm; capitula without filaments ±8 x 5.5-6 mm, prior to anthesis moriform, the obtuse 4-angulate fl-buds microscopically papillate; bracts narrowly elliptic ±1.5 x 0.4 mm, carinate and glabrous dorsally, microscopically ciliolate; flowers 4-merous 4-androus, glabrous, some lower ones staminate and a little longer than the rest; calyx membranous campanulate 0.3-0.4 mm, shortly 4-lobulate, each lobule sometimes tipped with a minute clavate setule; corolla narrowly turbinate 2.3-2.5 mm, the shallowly concave 1-nerved lobes 0.8-1 x 0.6-0.7 mm, scarcely thickened at tip; filaments pink, free to base, exserted ± 5 mm. Pods not seen, described in protologue as 30-40 x 7 mm, the replum densely setose.

Distribution and Ecology - On brushy hillsides near 2000 m, known only from the valley of río Urubamba in prov. Urubamba and adj. La Convención in depto. Cuzco, Peru.—Fl. IX-l—Mechicallo. Map 47.

Discussion:

The poorly known M. cuzcoana has all technical characters of subser. Castae and appears only precariously distinct from M. schrankioides var. sagotiana, which it resembles in small, glabrous or almost glabrous calyx, in essentially glabrous stems and dark green, facially glabrous leaflets, in shorter leaf-stalks, and in submontane habitat. Mimosa insidiosa, with which Harms considered it comparable, has retrorsely hispid stems, continuously marginate leaflets, and is endemic to eastern Brazil.

The specimen from Lapanmarca in prov. La Convencion, Soukup 817 (F!), cited in the protologue of M. cuzcoana, differs as follows: aculei smaller (to ±1 mm), accompanied by loosely retrorse setaculei; foliage pilosulous, the lfts finely so on both faces and in addition setulose-strigulose beneath; lfts of longer pinnae 20-30-jug., the longer ones ±9-12 x 1.5-2.5 mm, less emphatically venulose beneath. I am unable to classify this collection satisfactorily.

Distribution:Peru South America|

Narratives:Mimosa cuzcoana