Monographs Details: Mimosa revoluta (Kunth) Benth.
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:Acacia revoluta Kunth, Mimosa gonoclada Benth., Mimosa soratensis Benth.
Description:Species Description - Stiffly branched bushy and potentially arborescent shrubs 1-5 m with usually deeply channeled and stoutly ribbed stems armed at or immediately below all or most nodes with 1 infrapetiolar and 2 infrastipular aculei, these commonly stout ascending or horizontal, basally dilated and stramineous or brownish, sometimes reduced to small weak conical prickles, the obtuse ribs of internodes either smooth, papillate, or rarely densely setaculeate and like all lf-axes and peduncles densely finely or minutely puberulent with erect hairs 0.05-0.2(-0.3) mm, the foliage olivaceous subconcolorous, the plane lfts glabrous sublustrous above, dull glabrous beneath, minutely ciliolate, the globose or ellipsoid capitula either solitary in axil of relatively ample primary lvs, or on axillary branchlets, then either subtended by smaller simplified lvs or pseudo-fasciculate. Stipules erect linear-subsetiform 1.5-5 x 0.2-0.4 mm, early dry caducous. Leaves dimorphic or potentially so: lf-stk of primary lvs (2.5-)3-6 cm, the petiole 3.5-10 mm, at middle 0.5-1.1 mm diam., the interpinnal segments 4-10, the ventral groove bridged between pinna-pairs and charged always between the first pair and sometimes also between succeeding ones with a subsessile pitted nectary 0.4-1.2 mm diam.; pinnae (3-)4-6-jug., a little decrescent proximally, the axis of longer distal ones 2-4 cm, the interfoliolar segments (1.2-)1.5-2.8(-3.5) mm; lfts of longer pinnae 11-16-jug., a little decrescent at each end of rachis, the first pair 0.4-1.2 mm distant from erect or refracted paraphyllidia 0.3-0.9 mm, the blades narrowly oblong or oblong-elliptic from obtusangulate or semicordate base, abruptly apiculate, those near mid-rachis (3-)3.5-6.5 x 0.9-2 mm, 3.2—4 times as long as wide, all veinless above, beneath weakly 1-2 (-3)-nerved from pulvinule, the midrib displaced to divide blade 1:2.5—3.5, simple or beyond middle 1—2-branched on posterior side, the branches sometimes anastomosing with the inner posterior primary nerve, the outermost posterior nerve, when present, short or obscure; lf-stks of axillary brachyblasts (sometimes developing after fall of primary lvs) 5-25 mm, the pinnae only 2-4-jug., their rachis to 5-20 mm, the lfts 6-10-jug., 2-5 mm long. Peduncles (1-) 1.5-4.5 cm; capitula without filaments 5.5-11 x 5.5-7 mm, prior to anthesis moriform, the obovoid fl-buds glabrous; bracts linear-spatulate or obovate 0.6-1 mm, ciliolate, caducous; flowers 5-(6)-merous diplostemonous, greenish-white or ochroleucous, all or almost all bisexual; calyx campanulate submembranous brownish 0.6-1.8(-2.2) mm, the tube minutely puberulent or glabrate externally, the short-denticulate or merely undulate rim ciliolate; corolla narrowly trumpet-shaped (2.3-)2.5- 3.3(-4.2) mm, the erect or spreading lanceolate lobes 0.8-1.4(-2.2) x 0.5-0.8 mm, glabrous dorsally, papillate at margin; filaments fused at very base into an obscure stemonozone, exserted 3-4.5 mm; anthers ovate 0.6-0.7 mm. Pods 1-several per capitulum, sessile, in profile broad-linear recurved through 1/3 circle to coiled backward through 1.5 circles, measured along curvature 20-60 x 6.5-10 mm, (4-)5-8(-10)-seeded, the stout replum 1.3-1.6 mm wide, its convex and rarely also its concave periphery with 1-3 rows of straight erect stramineous aculei 1-5 mm, the firmly papery, green or fuscous valves low-colliculate over each seed and depressed between them, externally minutely puberulent overall and either unarmed or aculeate like the replum but more shortly so, internally smooth orange eseptate, when ripe separating entire from replum along both sutures but more readily along the seminiferous one; seeds obliquely basipetal, compressed-obovoid 4-5 x 3—4 mm, the brown or olivaceous testa smooth sublustrous.

Distribution and Ecology - On dry hillsides, on rocky streambanks, and surviving at the edge of fields and terraced milpa, 2500—3300 m, discontinuously dispersed along the Peruvian and Bolivian Andes in lat. 7°-18°S: in Peru from Cajamarca s. to Cuzco, mostly on the Amazon slope but crossing the crest w.-ward into Ancash; Nor- and Sur-Yungas in La Paz and Cochabamba, Bolivia.—Fl. almost throughout the year, the fls and ripe or ripening fruits often coeval. Map 5.

Discussion:

This superficially variable species appears in Bentham’s revision (1875: 425, 427) under three names: M. revoluta, M. gonoclada and M. soratensis. Only the first of these was credited with petiolar nectaries, although in reality all are alike in this respect. Granted the nectary, M. soratensis is essentially identical to M. revoluta. Mimosa gonoclada was likened by Bentham to M. (Andinae) montana and distinguished from it chiefly by deeply sulcate branches (a feature common in M. revoluta) and scabrous or, as I would term it, densely setaculeate stems. Bentham interpreted this array of setaculei as aculei sparsi, therefore significantly different in kind from the usually three infranodal aculei of ser. Andinae. But M. gonoclada, of which the holotype is now supplemented by Beck 7458 (NY) from prov. Ayopaya, Cochabamba, has setaculei supplementary to, not replacing, the primary nodal prickles characteristic of M. revoluta, together with its nectaries and coiled pods. This scabrous form of M. revoluta, known only from the southern edge of the whole range of the species, may deserve some subordinate taxonomic rank, but is emphatically not specifically distinguishable.

The earliest known collection of M. revoluta is in the Ruiz and Pavón collection, distributed as "Mimosa cornigera" (BM!).

Distribution:Bolivia South America| Cochabamba Bolivia South America| La Paz Bolivia South America| Peru South America| Cajamarca Peru South America|

Narratives:Mimosa revoluta
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