Monographs Details: Mimosa reduviosa 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.
Synonyms:Mimosa bocainae Barneby
Description:Species Description - Slender unarmed, virgately erect microphyllidious shrubs ± 1 m, with defoliate scabrous trunk distally few-branched and densely foliate, the homotinous stems and peduncles clad in deflexed, finely flagelliform setae to 1.5-2 mm, the lf-axes similarly but antrorsely silky-setose, the imbricate firm olivaceous subconcolorous lfts glabrous facially, continuously pallid-marginate and finely setulose-ciliolate, the subglobose capitula solitary in the axil of coevally expanding lvs, forming a short foliate pseudoraceme terminal to most branchlets, the fruits persisting on the trunk below new leafy growth. Stipules firm erect lanceolate 2-3.5 x 0.4-0.6 mm, either glabrous or setulose dorsally, densely setulose-ciliate, 3-4-nerved, persistent. Leaf-stalks including hard livid pulvinus 1-2.5 mm; pinnae stiffly ascending 1-jug., the rachis 2-3.5 cm, the interfoliolar segments 0.6-1 mm; lfts 20-31-jug., the small first pair less than 0.5 mm distant from subulate paraphyllidia concealed by setae, the blades linear-oblong obtuse from bluntly auriculate base, those near mid-rachis ±3.5-6 x 0.75-1.2 mm, 4-5 times as long as wide, all veinless above, the convex dorsal face finely 4-5-nerved from pulvinule, the simple midrib moderately displaced, the anterior and the inner posterior nerve both produced nearly or quite to blade apex, the pallid margin scarcely 0.1 mm wide, the ascending cilia free for 0.2-0.5 mm. Peduncles ± 15-35 mm; capitula without filaments 5.5-6.5 mm diam., prior to anthesis moriform but silky-setulose overall; bracts linear-oblanceolate 2-2.5 x 0.3 mm, dorsally 1 (-3)-nerved glabrous, setulose-ciliolate; flowers 4-merous 4-androus, mostly bisexual; calyx pappiform 1.3-1.7 mm, the lobes decompound to within 0.3-0.5 mm of base; corolla narrowly funnelform 2.2-2.7 mm, the narrowly ovate concave, scarcely thickened but dorsally carinate lobes 0.7-0.8 x 0.45-0.6 mm, externally silky-setulose on either side of keel; filaments vivid pink, united at base into a stemonozone 0.3-0.5 mm, exserted 6-6.5 mm; ovary at anthesis glabrous. Pods to 10 per capitulum, sessile, in profile oblong-elliptic obtuse at both ends, 10-12 x 5-5.5 mm, mostly (3-)4- seeded, the replum 0.7-0.8 mm wide, scabrously setulose along back, along sides charged with dense files of stout erect stramineous tapering setae to 4-5 mm, the papery stramineous valves low-colliculate over each seed, finely ascending-setose, breaking up when ripe into individually dehiscent articles 2-3(-3.5) mm long, these becoming free from replum but long retained in a mesh of replar setae; seeds (not seen fully ripe) compressed-ellipsoid ±3-3.5 x 2 mm, the testa light brown.
Distribution and Ecology - On river bank in cerrado and in brejo at edge of campo, at elevations not recorded, known only from the headwaters of rio Jaguariaíva in mun. Piraí do Sul and Jaguariaíva, n.-e. Paraná, Brazil.-Fl. XI-?
Mimosa reduviosa appears close kin to allopatric M. bocainae, which it resembles particularly in the retrorsely directed, scaberulous setae of the stems and peduncles (whence the epithet, from reduvium = hangnail). It differs from this principally in three-, not two-nerved leaflets and in globose, not ellipsoid capitula. Also similar in habit of growth is M. paranapiacabae, but while virtually sympatric with M. reduviosa this differs more decisively in antrorse, smooth setae of stems and peduncles, in 5-9 (not ± 3)-nerved stipules, in fewer (8-13, not 20-31) pairs of leaflets, and in five-, not one-nerved floral bracts. Despite the proximally retrorse (but distally often upswept) orientation of cauline setae, M. reduviosa and M. bocainae together appear more closely related to species with antrorse basifixed terete cauline setae than to habitally similar M. ourobrancoensis of subser. Obstrigosae. The setae of the latter are not simply retrorse, but also stiffly appressed their whole length, dorsiventrally compressed, and minutely spurred at base.
Distribution:Brazil South America
| Paraná Brazil South America