Mimosa lacerata 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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Synonyms
Acanthopteron laceratum (Rose) Britton, Mimosopsis glutinosa Britton & Rose, Mimosa biuncifera var. horrida Miranda
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Description
Species Description - Stiffly wide-branched, potentially arborescent shrubs 1-4 m, strongly armed at nodes with (l-)2 broad-based fuscous aculei 3—10(—12) mm, the young growth finely puberulent and granular but the concolorous lfts facially glabrous or glabrate, ciliolate, the foliage dimorphic, the lvs of barren long-shoots ample and pluri-pinnate, those of floriferous spurs much smaller and simpler, the inflorescence of globose capitula on brachyblasts along flexuous annotinous branches either accompanied or not by contemporary lvs. Stipules of primary lvs linear-attenuate or setiform 1.5-5 mm, obscurely 1-nerved, those of brachyblasts shorter. Leaf-formula of primary lvs iv-xiii/15-22, the lf-stk 2-9(-12) cm, the rachis of longer pinnae 1.5-3 cm, the linear or narrowly lance-oblong, acute or apiculate lfts attaining (2.5-)3- 6 x 0.7-1.8 mm, 3.2-4.3(-5) times as long as wide, all tenuously (l-)2-nerved from pulvinule, the scarcely excentric midrib faintly pinnate, the posterior nerve very short and fine; lf-formula of brachyblast lvs ii-v/9-15, the lf-stks ±1-2 cm, the rachis of longer pinnae 1 cm or less, the longer lfts 2-3 mm. Peduncles mostly 2-5 together, 10-25 mm, much thickened in fruit; capitula without filaments 5-7 mm diam., moriform, the fl-buds thinly or densely puberulent at tip; flowers of M. aculeaticarpa except for shorter calyx, this 0.55-0.8 mm long, not more than 1/3 as long as corolla. Pods several per capitulum, commonly stipitate but occasionally subsessile, the stipe ordinarily 1-7 mm, the undulately broad-linear body in profile 30-65 mm long and without lacerate wing of replum 6-8 mm wide, 5-8-seeded, the scarcely dilated replum charged along dorsal rib with a continuous or subcontinuous, single file of laterally compressed, broad-based, lustrous brown setaculei to (2.5-)3-7(-8) mm tall usually all confluent into a jagged fringe, but sometimes some or most narrowly discrete, the livid, glabrous but densely granular and resinous valves almost plane, when ripe becoming papery and separating from replum in one piece.
Distribution and Ecology - In desert matorral and deciduous brush-woodland, 1350-2520 m, commonly but not exclusively on calcareous substrates, colonial along the plateau slope of Sa. Madre Oriental from Hidalgo and adj. Querétaro to n. and centr. Oaxaca, w. through Morelos into e. Guerrero.—Fl. (III-)IV-VI, the fruits long persistent among the expanded summer foliage.
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Discussion
Mimosa lacerata rather closely simulates M. aculeaticarpa in most respects, but differs in the shorter calyx, the exaggerated armature of the pod, and further from tropical montane Mexican forms of that polymorphic species in bimodal branching pattern, providing for vernal flowers from brachyblasts and summer foliage from long-shoots. A similar winged fruit, in which the setaculei of the replum are greatly dilated at base and confluent into jagged margin, has developed in lowland M. bahamensis, but is there accompanied by a distinctive indumentum and leaf-formula. Since its description nearly a century ago the pod of M. lacerata has been found to vary considerably in length of stipe, in width of body, and development of the marginal wings, of which the component setaculei are sometimes found partly or largely separate to the base, as in the type-collection of Mimosopsis glutinosa. From the material seen, much of which lacks mature fruits, it appears that the typical broad, long-stipitate and continuously broad-winged pod is prevalent from the Tehuacan Desert south- and southwest-ward, and the narrower, often shortly stipitate and less emphatically winged or only strongly setaculeate pod prevails northward from Puebla into Querétaro, but is also present at the margin of the Tehuacán Desert (e.g., M. glutinosa). The intraspecific variation requires systematic study in the field of the spring and summer aspects of each population.
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Distribution
Mexico North America| Guerrero Mexico North America| Hidalgo Mexico North America| Oaxaca Mexico North America|