Mimosa leptocarpa Rose
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Authors
Rupert C. Barneby
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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.
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Family
Mimosaceae
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Scientific Name
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Type
194. Mimosa leptocarpa Rose, Contr. U.S. Natl. Herb. 1: 326. 1895. —"[Mexico. Colima:]Manzanillo, March 2 to 18, 1891. [E. Palmer] No. 1341."—Holotypus, US!; isotypi, GH! = NY Neg. 11984, NY!-Neomimosa leptocarpa (Rose) Britton & Rose, N. Amer. Fl. 23(3):
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Synonyms
Neomimosa leptocarpa (Rose) Britton & Rose, Mimosa argillotropha B.L.Rob., Mimosa sepiaria Benth.
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Description
Species Description - Amply leafy, bushy or sarmentose shrubs armed on bluntly 5-ribbed stems and on both dorsal and lateral ribs of lf-axes with files of sharp recurved, broad-based aculei ±1-2 mm, minutely strigulose almost throughout with fine appressed or weakly ascending hairs less than 0.2 mm, nowhere glandular nor setose, the lvs bicolored, the thin-textured lfts dull brown-olivaceous above, pale-olivaceous beneath, the inflorescence a pyramidal panicle of small globose capitula exserted 1.5-2.5 mm from foliage. Stipules erect, subulate-setiform 1.5-3 x 0.2-0.3 mm, 1-nerved, persistent. Leaf-stalks of larger lvs 6-11 cm, the petiole including livid pulvinus 1.530 x 0.6-0.9 mm, the longer interpinnal segments 10-18 mm, the narrow ventral sulcus bridged between pinnae but espiculate; pinnae 4-6-jug., accrescent distally, the rachis of longer ones 3-4 cm, the longer interfoliolar segments 3-5 mm; lfts of larger pinnae 7-1 l(-12)-jug., subdecrescent at each end of rachis, the blades oblong or oblong-elliptic from obliquely subtruncate inequilateral base, abruptly sharply apiculate, the larger ones 7-12 x 2.5-5 mm, 2.2-3 times as long as wide, all essentially veinless above, beneath delicately 2-nerved from pulvinule, the centric, immersed or scarcely prominulous midrib faintly pinnate, the posterior nerve expiring below mid-blade. Peduncles 2-5 per node of panicle, 10-17 mm; capitula without filaments 6-6.5 mm diam., prior to anthesis moriform, the clavate obtuse fl-buds glabrous; bracts oblanceolate 0.5-0.7 mm, puberulent; flowers 5-merous haplostemonous or some randomly 6-8(-9)-androus, glabrous throughout; corolla described as white, darkening when dry, vase-shaped, 3-3.2 mm, the erect-spreading ovate lobes 0.8-1 x 0.6-0.7 mm, weakly 1-nerved; filaments free to base, exserted 3-4 mm; ovary puberulent. Pods solitary or few per capitulum, stipitate, the stipe 6-14 mm, the body in profile broad-linear, abruptly contracted into stipe, obtuse, 17-13 x 1.3-2.2 cm, piano-compressed, the shallowly undulate replum 0.4-0.5 mm wide, the papery, when ripe lustrous brown glabrous valves delicately venulose, minutely umbonulate over each seed, readily separating from replum but rather tardily and irregularly breaking up into ±10-12 free-falling articles a little wider than long; seeds discoid, in broad profile 5-5.5 x 4.5-5 mm, the smooth sublustrous testa brown at margin but paler at pleurogram.
Distribution and Ecology - In drought-deciduous matorral below 100 m, scattered along the Pacific lowlands of s.-w. Mexico in Colima and w. Guerrero, seldom collected. -Fl. X-XII(-?).
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Discussion
Mimosa leptocarpa made two appearances in North American Flora, the flowering state as a monotypic group Argillotrophae, the fruiting state as Neomimosa leptocarpa. In North America it was morphologically isolated until the recent discovery in Oaxaca of M. antioquiensis, and its connection with the South American species of ser. Plurijugae escaped notice. Its mostly pentamerous flowers that give rise to broadly ribbonshaped, stipitate and about 10-12-ovulate pods combined with elaborately bipinnate leaves and cat’s-claw armament of stems and leaf-stalks are in close agreement with M. antioquiensis and M. lemniscata, from both of which it differs, however, in fewer larger leaflets and isolated habitat along the coastal plain of Colima and Guerrero. In the limited number of flowers available for dissection I found the androecium for the most part strictly haplostemonous, one to three and exceptionally four complementary stamens appearing randomly in some lower flowers.
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Distribution
Mexico North America| Colima Mexico North America| Guerrero Mexico North America|