Mimosa malacophylla

  • Title

    Mimosa malacophylla

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Mimosa malacophylla A.Gray

  • Description

    105. Mimosa malacophylla A. Gray, Boston J. Nat. Hist. 6(Pl. lindheimer. 2): 182. 1850.— "On the Rio Grande, Texas, Mr. Charles Wright. . . near Monterey, Northern Mexico, by Dr. Gregg and Dr. Edwards . . . east of Rinconada, by Dr. Gregg in 1848."—Lectotypus (Isely, 1971b: 419): Gregg 207 from Rinconada, GH!; syntypi, Gregg in 1847, Edwards & Eaton 22 in 1846, annotated by Bentham, NY!

    M. malacophylla var. glabrata Bentham, Trans. Linn. Soc. London 30: 423. 1875.—"Berlandier, n. 815 and 2235."—Holotypus, Berlandier 815 = 2235, K (hb. Hook., s. loc.)!; isotypus, no. 815 e "San Fernando, Tamaulipas," NY!

    M. wootoni Standley, Contr. U.S. Natl. Herb. 23: 364. 1922.—"Type from Hacienda Buena Vista, Tamaulipas (Wooton, June 14, 1919. . .)."—Holotypus,US 989828!—Referred to M. malacophylla by Isely, 1973: 104.

    Scandent or, when unsupported, diffuse, weakly fruticose subshrubs attaining 4.5 m, armed at least on main stems and on most lf-axes with files of cat’s-claw aculei 1.5-2.5 mm (random distal branchlets almost unarmed), the stems and foliage densely pilosulous with soft erect pallid hairs to 0.3 mm or minutely thinly puberulent, the broad thin-textured lfts facially either pilosulous, puberulent, or glabrous (but then minutely ciliolate), the inflorescence of ellipsoid or subglobose capitula either simply pseudoracemose or paniculate, either fully exserted from foliage or proximally foliate. Stipules subulate-setiform 1-8 mm, 1-nerved. Leaf-formula iii—vi/ 4-7, the lf-stks (4-)5-16 cm, spiculate between pinna-pairs, the rachis of longer pinnae 2-4 cm; lfts subsymmetrically ovate, ovate-elliptic or (especially the distal pair) obovate, abruptly mucronulate or apiculate, attaining 7.5-14 x 4.5-9 mm, 3-nerved dorsally, the midrib pinnately 3-5-branched on each side. Peduncles (1—)2—5 per node, (5-)8-20 mm; capitula without filaments 5-14 x (4-)4.5-6.5 mm, prior to anthesis moriform, the pyriform-obovoid fl-buds silky- puberulent, the receptacle becoming 4-10 mm; pedicels 0.1-0.5 mm; flowers (4-)5-merous, but the androecium variously reduced to 5-10 filaments, and only 5-6 antheriferous; calyx campanulate 0.3-0.6 mm, the rim minutely denticulate and ciliolate; corolla 1.8-2.7 mm; filaments white, united at very base below stipe of ovary, exserted 4-4.5 mm; anthers ovate 0.4-0.6 mm, the connective sometimes minutely produced between anther-sacs. Pods 1-6 per capitulum, the stipe 6-16 mm, the body in profile broad-linear 50-90 x 8-12.5 mm, falcately recurved, 4-10- seeded, the replum either unarmed or remotely aculeolate, shallowly constricted or almost straight, often vestigially puberulent, the glabrous or glabrate valves low-bullate over each seed, the indehiscent, free-falling articles 8-13 mm long.

    Shrub-thickets, hedges, and ditch-banks, below 400 m, locally common in the lower Rio Grande valley in Texas, downstream from Kinney County (Isely, 1973, map 34), thence s. through e. Coahuila and centr. Nuevo León to extratropical Tamaulipas, Mexico—Raspilla, raspa-huevos.

    Mimosa malacophylla is notable especially for its imperfect androecium and for the shape of the anthers. It resembles M. hondurana in small calyx, but differs in much smaller, less oblique leaflets, in minutely pedicellate flowers, and in habitat and dispersal. Mimosa sinaloensis, similar in general facies, differs in deeply campanulate calyx and lacks interpinnal spicules.