Mimosa monancistra

  • Title

    Mimosa monancistra

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Mimosa monancistra Benth.

  • Description

    51. Mimosa monancistra Bentham, Pl. hartw. 12. 1839.—No locality given, this supplied by Bentham, Trans. Linn. Soc. London 30: 425. 1875: "Mexico. Aguas Calientes."—Holotypus, Hartweg 70, K! = KNeg. 15529 = MICH Neg. 612.

    M. similis Britton & Rose, N. Amer. Fl. 23(3): 166. 1928.—"Minas de San Rafael, San Luis Potosí, May, 1911 ,[C. A.] Purpus 5179"—Holotypus, NY!

    Stiffly branched xeromorphic shrubs attaining 8-28 dm, armed at most or sometimes at only scattered or random nodes with a solitary, gently recurved infrapetiolar aculeus 2-5 dm, the young branchlets and the foliage except for often glabrous upper face of lfts softly minutely puberulent or silky-puberulent, the oblong capitula solitary or 2-3 together in a succession of lf-axils along homotinous long-shoots, prior to anthesis sometimes pseudoracemose but the fruits immersed in foliage. Stipules linear-subulate 0.6-2.5 mm, weakly 1-nerved, early incurved and yellowing, finally deciduous. Leaf-formula ii-iv (-v)/(3-)4-9(-10), the lf-stks 9-37 mm, 3-ribbed and sometimes aculeolate dorsally, the ventral sulcus bridged between pinna-pairs but spicule 0; rachis of distal pinnae 6-12(-20) mm; lfts narrowly ovate or oblong-elliptic, obtuse or subapiculate, the larger ones (2-)2.5-4.5(-5) x (0.8-)l- 1.5(—1.7) mm, ±2.2-3.3 times as long as wide, all weakly (l-)2-nerved dorsally, but only the moderately displaced midrib finely prominulous dorsally. Peduncles 4-16 mm; capitula without filaments 6-11 x (4-)4.5-6 mm, (1.2-) 1.3-2 times as long as diam., the receptacle 3-8 mm, the pyriform obtuse fl-buds puberulent, exceeding the bracts; flowers 5-merous 10-androus, all bisexual; calyx membranous, campanulate or turbinate, (0.9-)l-1.4 mm, externally puberulent, the deltate-triangular teeth 0.1-0.4 mm; corolla vase-shaped 2-2.8(-3) mm, ± twice as long as calyx; filaments pink, united at extreme base, exserted 4-6 mm. Pods 1-5 per capitulum, subsessile, in profile linear, lunately recurved, 20-35 x 4.5-5.5 mm, (3-)4-5-seeded, the replum either shallowly or scarcely constricted, the replum and valves alike both puberulent and hispid overall with short plain hairs and erect, smooth or scaberulous setae, the setae of replum to 2-3 mm, those of valves more slender and shorter, the ripe valves bullately distended over each seed, breaking up into free-falling, individually dehiscent articles 4-5 mm long.

    On dry stony hills and in foothill washes, in a variety of brush-woodland and savanna-like associations, locally abundant and forming thickets, scattered around the s. margin of the Mexican Plateau below 2200 m, from the middle Lerma valley in Jalisco e. through the Bajío to Querétaro, thence n. to the Nazas valley in e. Durango, and through San Luis Potosí to the Gulf lowlands at 140 m near 24°N in Tamaulipas; s. of the Transverse Volanic Range in Morelos.—Fl. (IV-)V-X. — Garpatillo; garruña.

    The type of M. similis appears to differ from typical M. monancistra only in scaberulous rather than smooth setae on the pod.

    McVaugh (1987: 215) described M. monancistra as so abundant in parts of northern Jalisco as to color, when in flower, whole pastures and hillsides.