Mimosa niederleinii Burkart

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 niederleinii Burkart

Type

464. Mimosa niederleinii Burkart, Darwiniana 7(4): 523. 1947 & 8(1): 162, icone adjecto. 1948.—"Argentina. Misiones: ‘Varana, Misiones, Agosto 23 de 1887,’ leg. Gustavo Niederlein, Expedición de la Comisión de Límites, Secc. Hist. Nat. etc., no. 1117."—Ho

Synonyms

Mimosa niederleinii var. riograndensis Burkart, Mimosa niederleinii Burkart var. niederleinii

Description

Species Description - Prostrate and pliantly diffuse or trailing, unarmed microphyllidious subshrubs to ± 1 m, the stems, lf-stks and axillary peduncles either strigose or hispid with either smooth or scaberulous, exceptionally plumulose, either forwardly appressed or widely divaricate setae to 1-3 mm commonly mixed with minute puberulence, the foliage notably bicolored, the ventrally convex lfts brown-olivaceous lustrous and glabrous above, beneath paler dull and glabrous to puberulent or sometimes in addition thinly strigose, the cylindric fl-spikes 1—2(—3) together on very slender peduncle longer than petiole of subtending lf but shorter than its pinnae, hence immersed in foliage. Stipules firm, erect or in age deflexed, linear-attenuate 2-5 x 0.2-0.6 mm, pubescent dorsally like adjacent stem, subpersistent. Leafstalks 4-20 mm, at middle 0.3-0.6 mm diam., obscurely sulcate ventrally, espiculate; pinnae 1-jug., the rachis (2-)2.5-8.5 cm, the interfoliolar segments 0.5-1.3 mm; lfts (28-)30-54-jug., conspicuously decrescent near each end of rachis, symmetrically so distally but proximally more so on anterior side of pinna-rachis, the first pair 0.3-0.6 mm distant from unequal linear-subulate paraphyllidia 0.5-1.2 mm, the blades linear-oblong or -lanceolate from obtusangulate or obtusely auriculate base, deltately apiculate or obtuse, those near mid-rachis 3.5-7.5 x 0.8-1.4 mm, all smooth veinless above, beneath 2-3- nerved from pulvinule, the moderately displaced midrib alone prominent, simple or weakly 1-3- branched on each side above mid-blade, the posterior nerve(s) weak and short. Peduncles 1.5-3.5 cm; flower-spikes without filaments (10-) 12-25 x 3.5-4 mm, the fls subcontiguous along receptacle, the fl-buds surpassing their subtending bract, gray-puberulent; bracts linear-setiform 0.7-1 x 0.2-0.3 mm, dorsally puberulent 1-nerved, setose-ciliolate with weak ascending setulae 0.3-0.8 mm or eciliolate flowers 4-merous 4-androus, some lower ones staminate; calyx including short, sometimes obsolescent fringe of setulae 0.4-0.7 mm, the submembranous, deltately lobulate tube 0.3-0.5 mm, the cilia not over 0.4 mm; corolla subtubular 1.5-2.1 mm, below middle retrostrigulose, beyond middle puberulent with short spreading-ascending trichomes, the ovate 1-nerved, shallowly navicular lobes 0.5-0.7 x 0.3-0.5 mm; filaments pink, free to base, exserted 4.5-5 mm. Pods scarcely known, those of var. riograndensis described as 25-30 x 4.5-5 mm, 3-4-seeded, strigose overall.

Distribution and Ecology - On river banks and at edge of brejo in the region of campo and araucaria forest between 700 and 950 m in extratropical Brazil, from mun. Jaguariaíva in e. Paraná s. to n.-e. Rio Grande do Sul; and apparently disjunct, presumably near 450 m, near Fracrán in depto. San Pedro, Gob. Misiones, Argentina.—Fl. XII-IV.

Discussion

The wholly extratropical M. niederleinii resembles in a general way M. reptans and M. axillaris, but differs in spiciform capitula, disregarding filaments 3-6 times as long as their diam. The strongly bicolored, ventrally convex and glossy green, dorsally concave and pallid leaflets combined with corollas clothed below middle with retrorse hairs suggest affinity to M. perdusenii and M. dryandroides. These, however, are erect subshrubs with globose or only incipiently elongating capitula, their leaflets are densely felted beneath, and their flowers are retrostrigulose overall.

Burkart described three varieties of M. niederleinii, differing in pubescence of stems and leaflets. The var. niederleinii, represented by the type alone, had forwardly appressed cauline setae and leaflets at once puberulent and strigose dorsally. The var. riograndensis was said to differ only in leaflets either glabrous or simply puberulent but not strigose beneath; whereas var. pseudolepidota had spreading, plumose cauline setae. The indumentum of the latter coincides with a modified paleaceous calyx in what is here interpreted as a specifically significant syndrome of characters, but vars. riograndensis and niederleinii lack differences correlated with pubescence. Among duplicates of collections identified by Burkart as var. riograndensis I find these intermediate or contradictory forms: Hatschbach 24207 (NY) from Piraquara, Paraná has proximal leaflets of some leaves densely setose beneath but distal ones puberulent only; and Smith and Klein 11316 (US) from município Lages, Sta. Catarina, has stems hispid like those of var. pseudolepidota but with perfectly smooth setae. The var. riograndensis cannot be exactly characterized and is here reduced to synonymy of M. niederleinii.

Distribution

Brazil South America| Paraná Brazil South America| Rio Grande do Sul Brazil South America| Argentina South America| Misiones Argentina South America|