Mimosa velloziana Mart.

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 velloziana Mart.

Type

323. Mimosa velloziana Martius, Flora 22(1, Beibl. 1): 9 [= Herb. fl. bras. 185]. 1839, based on M. viva Vellozo, Fl. flumin. icon. 11: t. 33. 1829, nom. illeg., non Linnaeus, 1753.-Typus, the cited plate! M. velloziana sensu Bentham, 1841: 390 ("Veliosia

Synonyms

Mimosa viva Vell., Mimosa heterocarpa C.Presl, Mimosa velloziana var. jiramenensis (H.Karst.) Benth., Mimosa velloziana var. glabra Wawra, Mimosa maxonii Standl., Mimosa velloziana var. oranensis Burkart

Description

Species Description - Diffusely arching and scrambling, vine- or briar-like, subherbaceous and softly woody shrubs with prickly canes potentially attaining 2.5 m in length and 9 mm diam., the terete or ribbed (but not 4-angular) homotinous stems together with dorsal rib of petioles armed with files of sharp, stramineous brown-tipped, broad-based recurved aculei to 1.5-3.5(-4) mm with or without slender retrorse setaculei and fine erect pallid villi to 0.3-0.5 mm, the broad papery lfts bicolored, green or purplish- to brownish-tinged and glabrous above, beneath olivaceous and commonly thinly strigose and sometimes in addition finely pilosulous, less often quite glabrous, the globose capitula commonly axillary to contemporary lvs or some later ones forming a simple or paniculately forking pseudoraceme exserted 1-3 dm from foliage. Stipules oblong or lance-ovate obtuse, erose or abruptly apiculate 3-6 x (0.8-)l-2.4 mm, the prominently 3-several-nerved blades becoming dry but persistent. Leaf-stalks (disregarding obviously diminished distal lvs) 2.5-7(- 8) cm, at middle 0.5-1.4 mm diam., the ventral groove broad and open, scarcely depressed below level of delimiting petiolar ribs, the spicule small or lacking; pinnae 1-jug., the rachis of each including livid wrinkled hispidulous pulvinus (8-) 10-22 mm, the proximal pair of lfts below or near middle and its anterior small lft subsymmetrically ovate-acuminate; paraphyllidia subulate or narrowly lanceolate 0.5-2.5 x 0.25-0.6 mm; blades of distal pair of lfts very obliquely or dimidiately lance-ovate or -elliptic, the larger ones (2.5-)3-6.5 x 1—3(—3.2) cm, ±2-3 times as long as wide, at base cordate on proximal side and cuneate on distal one, at apex deltate, triangular or short-acuminate, the margin with a single file of forwardly subappressed corneous setae free for 0.6-1 mm; primary venation of blades consisting of 4-6 nerves radiating from broad hispidulous pulvinule, the midrib asymmetric, forwardly incurved, the secondary venules from this and from posterior nerves incurved-ascending and weakly brochidodrome or sometimes expiring short of lft-margin, all these and fine, openly reticulate tertiary venules prominulous beneath, immersed but sometimes discolored above. Peduncles commonly 2-3 per node but some early ones solitary, 6-17(-22) mm; capitula globose, without filaments 5-6 mm diam.; bracts linear-lanceolate 1-2.6 x 0.3-0.6 mm, carinate dorsally, the membranous margins either smooth or with few pallid setulae to 0.3 (-0.4) mm; fl-buds obovoid, glabrous or apically puberulent; flowers 4-merous 4-androus, usually bisexual but some proximal ones often a little smaller and proportionately wider than the rest; calyx membranous 0.25-0.4 mm, the rim glabrous or minutely ciliolate; corolla narrowly fun- nelform 1.9-2.7 mm, 4-costate from base upward, the ovate-apiculate, apically incurved and slightly callous lobes 0.55-0.7 x 0.4-0.55 mm; filaments lilac or pink, sometimes fading whitish, free to base, exserted 3.5-5.5 mm; ovary an anthesis glabrous. Pods usually numerous per capitulum, sessile or abruptly contracted at base into a stipe to 1-1.5 mm, the piano-compressed body in profile narrowly oblong or broad-linear, when well fertilized (16-)20—42 x 8-11 (-13) mm, (1—)2—5-seeded, the replum in dorsal view 0.45-0.8 mm wide, at apex contracted into a slender beak 0.5-2 mm, its whole length armed on both dorsal and lateral ribs with stout erect setae 1-5 mm and rarely also minutely puberulent, the thin, green or anthocyanic, glabrous or puberulent valves when ripe stramineous, brownish or castaneous, low-colliculate and commonly setose (rarely esetose) over each seed, ultimately separating from replum and breaking up into articles 5.5-10 mm long; seeds compressed-obovoid 4-5.5 x 3-4.3 mm, the testa brown or olivaceous dull.

Distribution and Ecology - A weedy opportunistic mimosa, in open places forming diffuse tangles of prickly stems but potentially sarmentose through shrubs and small trees, of dubious nativity, now interruptedly widespread, from the lowlands to ±850 m in Mexico and to 1100 m on the Brazilian Planalto, in tropical N. and both tropical and warm temperate S. America, excluding the Antilles and Pacific S. America: s. Mexico (Nayarit, perhaps only adventive, not mapped; Oaxaca, Veracruz, Tabasco, Chiapas) s. to Panama; trans-Andean Colombia and Venezuela (Maracaibo and Orinoco basins); apparently not in the Guianas; Brazil from Pará s. to Paraná, erratically w. to middle Amazonia, to s.-centr. Goiás, and to the Paraguai valley in Mato Grosso; seemingly disjunct in the lower Paraná valley in Argentina (Misiones, Corrientes) and in the Andean foothills of Bolivia (Tarija) and Argentina (Salta); collected once at Lima, Peru, presumably introduced. —Fl. irregularly through the year. Map 50.

Discussion

Mimosa velloziana closely resembles M. sensitiva in habit, in armature of stems and leafstalks, and in shape of leaflets, but differs in a minute, non-pappiform calyx combined with a pod ordinarily 8 or more, not 4-7, mm wide. Populations differ in pubescence of foliage, in length and density of setae, and puberulence of the pod’s valves; and the pod itself, like that of M. casta, a species very similar except for a few more pairs of leaflets, varies considerably in width. But no correlated modes of variation are apparent in the main east-Brazilian range of the species. It is surmised that M. velloziana, like M. sensitiva, was originally native to eastern Brazil, south of Amazonia, and has spread outward from the present focus of abundance, very likely travelling with livestock, the hispid pod being well adapted to such transport. The relatively small samples examined from the two major populations in Argentina, on the lower Paraná river and in the Andean foothills of Salta respectively, confirm Burkart’s discovery of different pubescence patterns in these two disjunct regions. If, however, each derives from an independent introduction from Brazil, as seems plausible, it would not be surprising to find that slightly different genomes, fortuitously introduced, continue to reproduce their kind, presenting a locally uniform phenotype.

Both Martius and Bentham assumed that the M. viva portrayed by Vellozo was the plant common, at least formerly, within and around the city of Rio de Janeiro, where it was collected by most of the early botanists in Brazil, and there is no reason to question this. Mimosa heterocarpa, collected by Lhotzky either in coastal Bahia or in Guanabara in the early 1830’s, attained a spurious distinctness by faulty description of the pinnae as being four pairs per leaf, when in fact each is merely four-foliolate. Mimosa jiramenensis, maintained by Bentham as a variety, exemplifies the broad extreme in fruit measurement, but seems no more than this. Mimosa maxonii represents a relatively uncommon variant with pod-valves densely puberulent.

Distribution

Mexico North America| Nayarit Mexico North America| Tabasco Mexico North America| Veracruz Mexico North America| Chiapas Mexico North America| Oaxaca Mexico North America| Panama Central America| Colombia South America| Venezuela South America| Brazil South America| Pará Brazil South America| Paraná Brazil South America| Mato Grosso Brazil South America| Goiás Brazil South America| Argentina South America| Misiones Argentina South America| Corrientes Argentina South America| Salta Argentina South America| Bolivia South America| Tarija Bolivia South America|