Monographs Details: Mimosa paranapiacabae 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 bocainae Barneby, Mimosa reduviosa Barneby
Description:Species Description - Slenderly virgate microphyllous shrubs attaining 2 m, resembling M. bocainae in habit and small crowded lvs, but the setae of stems and lf-stks smooth, proximally less than 1 mm, toward inflorescence longer and finely flagelliform but not reflexed, the lvs at once shorter and simpler, the stipules striate, and the capitula globose. Stipules triangular-lanceolate 2-3.5 x 0.6-1.5 mm, dorsally glabrous and striately 5-9-nerved, pectinately ciliolate, persistent. Leaves sessile, the primary pulvinus obsolete, that of each pinna contiguous to stem; rachis of pinnae 6-15 mm, the interfoliolar segments 1-1.5 mm; lfts (6-)8- 13-jug., the blades linear obtuse from auriculate base, those near mid-rachis 4-7(-7.3) x 0.6-0.9 mm, (5.5-)6-9 times as long as wide, the dull olivaceous blades remotely minutely ciliolate but otherwise glabrous, the shallowly concave ventral face veinless, the slender centric midrib prominulous beneath, accompanied on posterior side by a weaker parallel nerve. Peduncles solitary 8-23 mm, 1-3 times as long as subtending If; capitula without filaments 4-7 mm diam., prior to anthesis either moriform or conelike depending on variable length of bracteal setae, bracts elliptic-oblanceolate 1.4—2.2 x 0.4—0.6 mm, striately 5-nerved, glabrous dorsally, the ascending cilia to 0.6-2 mm; flowers 4-merous 4-androus, many proximal ones staminate; calyx pappiform 1-1.2 mm, the tube almost 0, the setae weak, separate almost or quite to base; corolla narrowly vase-shaped 2.3-2.5 mm, the ovate cymbiform but scarcely thickened lobes 0.8-1 x 0.45-0.6 mm, minutely gray-pilosulous except for glabrous keel; filaments pink, free to base, exserted 7 mm. Pods ±3-12 per capitulum, sessile, in profile oblong-elliptic, abruptly short-apiculate 12-14 x 4-4.5 mm, 3-4-seeded, the replum to 0.8-1 mm thick, the ripe valves papery, low-convex over each seed, externally densely silky-setose with ascending lustrous setae to 2-3.5 mm, non-septiferous within, separating in one piece from replum and from each other; seeds (few seen) lentiform ±3 x 1.9 mm, the testa either dull brown and fuscous within the pleurogram or fuscous overall.

Distribution and Ecology - On arenitic outcrops near 900-1000(-?) m, local along rios Itararé and S. João, on landward slope of Sa. do Paranapiacaba in mun. Senges, Castro and Ponta Grossa, within 49°30'-50°W, 24°10'-25°S in e. Paraná, Brazil.—Fl. (IX-)X-III.

Discussion:

Mimosa paranapiacabae is notable in its immediate group for the modified leaves, of which the primary pulvinus is suppressed, the short, relatively paucifoliolate pinnae emerging directly from the stem. It differs from the closely related M. bocainae and M. reduviosa in smooth, never recurved cauline setae and in more numerous nerves of stipules and floral bracts. The nearly or actually sympatric M. hilariana differs in elliptic-oblanceolate or obovate, not linear leaflets, in campanulate, minutely toothed and ciliolate, not pappiform calyx, and in the weak infrapetiolar aculeus at each node, foreign to all close kindred.

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