Mimosa quitensis

  • Title

    Mimosa quitensis

  • Author(s)

    Rupert C. Barneby

  • Scientific Name

    Mimosa quitensis Benth.

  • Description

    33. Mimosa quitensis Bentham, J. Bot. (Hooker) 4: 408. 1842.—"Ravines round Quito, [Francis] Hall"—Holotypus,Hall 49, K(hb. Hook.)! = NY Neg. 1932 (top right).—Mimosopsis quitensis (Bentham) Britton & Rose in Britton & Killip, Ann. New York Acad. Sci. 35: 154. 1936.

    M. quitensis sensu Bentham, 1875: 427.

    Microphyllidious, openly branched arborescent shrubs 1-3 m, erratically armed on prominent intemodal ribs (but not on lf-stks) with stout, widely ascending broad-based aculei 3-8 mm, the young stems, lf-axes and peduncles pilosulous with grayish hairs ±0.15-0.3 mm mixed with livid granules, the lvs olivaceous subconcolorous, the plane thick-textured lfts glabrous above, usually puberulent beneath on side anterior to midrib, sometimes overall, the globose capitula in praefloration pseudoracemose at end of homotinous branchlets, becoming axillary to coeval or hysteranthous lvs, the pods immersed in foliage. Stipules erect subulate-setiform (1-) 1.5—5(—6) x 0.3-0.5 mm, puberulent dorsally, obscurely 1-nerved, persistent. Leaf-stalks (1.5-) 2-5(-6.5) cm, the petiole 5-11 x 0.5-0.8 mm, the longer interpinnal segments 3-5 mm, the deep ventral groove bridged between pinna-pairs and charged between most of them (at least the first, often all) with a weak spicule to 0.3 mm; pinnae (5—)6—12(-l 3)-jug., not or scarcely graduated, the rachis (5—)7—17(—19) mm, the longer interfoliolar segments 0.4-0.9 mm; lfts of longer pinnae (11-) 12-18(-20)-jug., decrescent at each end of rachis, the blades narrowly oblong or oblong-elliptic from obtusangulate base, obtuse or minutely apiculate, the larger ones 1.6-2.7(-3) x 0.5-0.8 mm, (2-)2.7-4 times as long as wide, all veinless above, beneath weakly 1-2-nerved from pulvinule, the midrib only a little forwardly displaced, the posterior nerve short or 0. Peduncles 10-26 mm, some early ones often solitary, the rest 2-4 per node; capitula without filaments 6.5-8 mm diam., prior to anthesis moriform, the obtuse fl- buds glabrous; bracts linear or linear-oblanceolate 0.5-1.1 x 0.1-0.2 mm puberulent; flowers 5-merous 10-androus greenish-white, mostly bisexual; calyx membranous campanulate 1-1.4 x 0.8-1.1 mm, the shallowly undulate rim microscopically ciliolate; corolla narrowly vase-shaped 3.3-3.8 mm, the narrowly ovate or lanceolate subacute, distally flaring lobes 1.2-1.5 x 0.5-0.85 mm; filaments white or cream-colored, united only at extreme base, exserted 4-5 mm. Pods solitary or to 10 per capitulum, sessile, in profile undulately linear, gently incurved (30-)40- 70 x 6-8 mm, (5-)6-8-seeded, the shallowly constricted or almost straight replum 0.6-1 mm wide, the papery valves low-colliculate over each seed, at first puberulent and granular overall becoming brown glabrate venulose, in dehiscence separating from replum along dorsal (convex) margin and inertly gaping to release the seeds, the cavity continuous; seeds obliquely basipetal, strongly compressed ±4 x 2.5-3.2 mm, the castaneous testa smooth, the pleurogram ±1.5 mm wide.

    In matorral and forming thickets on stony quebrada slopes and on roadsides, locally plentiful between 1300 and 2850 m in intermontane and Pacific valleys of the equatorial Andes in lat. 2°30'N-0°30'S, from Popayán in El Cauca, Colombia s. to neighborhood of Quito in Pichincha, Ecuador. —Fl. spasmodically throughout the year. — Guarango, applied also to M. andina and to some armed species of Acacia. Map 6.