Monographs Details: Mimosa psittacina 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
Synonyms:Mimosa pilulifera Benth., Mimosa daleoides Benth., Mimosa chrysastra var. chrysastra
Description:Species Description - Shrubby but of unknown stature, with slender livid defoliate trunks and densely foliate hornotinous branchlets concealed by floccose tomentum of fine sordid gray-plumulose setae to ±0.3-0.4 mm, the lf-axes and peduncles more shortly but as densely stellulate-tomentulose, the small thick-textured crowded lfts subconcolorous, glabrous above, beneath thinly stellate only around apex and on side anterior to the midrib, the narrowly ellipsoid capitula solitary and paired in the axil of contemporary lvs, immersed in foliage. Stipules erect, linear-subulate 2-4 x 0.30.5 mm, bluntly 1-nerved, persistent on defoliate trunks. Leaf-stalks 2.5-5 mm, tomentulose like stem; spicule 0; pinnae 1-jug., the rachis 2-4.5 cm, the interfoliolar segments 0.5-1.2 mm; lfts of longer pinnae 17-30-jug., subequilong or very gradually decrescent distally, the first pair 0.4-0.8 mm distant from ascending subulate paraphyllidia 0.3-1 mm, the blades oblong or oblong-elliptic obtuse from broadly auriculate base, those near mid-rachis 2.4-6 x 1-2.2 mm, 1.9-3 times as long as wide, above nerveless or almost so, beneath 3(-4)-nerved from pulvinule, the moderately displaced midrib simple or 1-branched beyond middle, the inner posterior nerve expiring beyond mid-blade, the outer one(s) much shorter. Peduncles very slender 12-23 mm; capitula without filaments 5-6.5 x 3 mm; bracts ±0.5 x 0.4 mm, thinly stellulate dorsally, persistent; flowers 4-merous 4-androus, only some distal ones bisexual; calyx submembranous shallow-cupular 0.15-0.2 mm, the rim minutely ciliolate; corolla turbinate 1.7-2.1 mm, densely yellowish-stellate and below the sinuses pallidly retrostrigulose, the ovate concave, scarcely thickened lobes ±0.8 x 0.7 mm; filaments (presumably ochroleucous, drying brown) free, exserted 2.2-3 mm; staminodia 0. Pods 1-5 from near top of receptacle, sessile, in profile undulately linear (12-) 14-24 x 3.5-4.3 mm, (2-)3-6-seeded, the shallowly constricted replum 0.5-0.6 mm wide, the papery valves low-colliculate over each seed, the replum almost and the valves quite concealed by sordid-yellowish stelliform setulae less than 0.2 mm tall, when ripe breaking up into individually dehiscent, free-falling articles 3-4.5(-5) mm long; seeds (few seen) plumply compressed- obovoid ±2.8 x 2.3 mm, the testa fuscous dull.

Distribution and Ecology - In unrecorded habitat, to be sought in submontane thickets near or above 1000 m, known only from the type, collected near 44°40'W in Sa. da Mantiqueira in s. Minas Gerais, Brazil. — Fl. ±XII.

Discussion:

In the context of related species with conjugate-pinnate leaves, most of which are of extratropical dispersal, the distinctive characters of M. psittacina are: a) thick-textured leaflets glabrous above, 3-nerved beneath and there thinly stellate on that part of the blade not covered by the leaflet next below it; b) ellipsoid, not globose capitula; c) corolla stellate on the lobes but retrostrigulose on the tube below the sinuses; and d) filaments free to the base. Mimosa chrysastra var. chrysastra, known only from Mt. Itambé in central Minas Gerais, resembles it overall, but has leaflets glabrous on both faces, glabrate (not tomentose) stems, globose capitula, corolla simply retrostrigulose, and shortly monadelphous filaments. Mimosa daleoides, which ranges south- and westward from São Paulo, has similar (though generally longer) capitula, but narrower leaflets tomentulose on both faces, a pod only 2-3 (not 3.5-4.3) mm wide, and once again monadelphous filaments. Mimosa pilulifera var. pseudincana, which ranges feebly north into southern Minas Gerais, differs in conspicuously bicolored 1-nerved leaflets glabrous above and tomentulose beneath, and capitula exactly globose, but has similar pod and filaments. The thick-textured leaflets thinly stellate where not covered by the next lower leaflet forcibly suggest distantly allopatric M. pilulifera var. pilulifera, but this (cf. Burkart, 1948: 122, fig. 18, lam. 12) again has little globose capitula and essentially 1-nerved leaflets.

Mimosa psittacina is represented in the Paris herbarium by three sheets of specimens so similar among themselves as to appear parts of one collection, but they are differently and ambiguously labelled. The sheet designated holotypus consists of several branchlets ticketed with the number 480d, but locality-data are lacking. The second sheet bears Saint-Hilaire’s number C1/489; the single stem thereon is ticketed 490d with query. The number must be mistaken, for C1/ 489 is described in Saint-Hilaire’s fieldbook (P) as a papilionacea. The third sheet repeats the corrupt number C1/489 and the specimen is ticketed 490d with query, to which is added the word Papagayo. Saint Hilaire’s fieldbook D records field-numbers ±490-515 taken in the Sa. da Mantiqueira in the general vicinity of Ibitipoca and Baependi, where Sa. do Papagaio is also located. Circumstantial evidence points to a common origin for all three sheets on Sa. do Papagaio.

Distribution:Brazil South America| Minas Gerais Brazil South America|