Mimosa quadrivalvis var. diffusa

  • Title

    Mimosa quadrivalvis var. diffusa

  • Author(s)

    Rupert C. Barneby

  • Scientific Name

    Mimosa quadrivalvis var. diffusa (Rose) Beard ex Barneby

  • Description

    190d. Mimosa quadrivalvis Linnaeus var. diffusa (Rose) Beard [in sched.] ex Barneby, comb. nov. Schrankia diffusa Rose, Contr. U.S. Natl. Herb. 1: 327, fig. 5. 1895. —"Very common along the beach... Manzanillo [Colima, Mexico], December 1 to 31, 1981. [E. Palmer] No. 1046." —Holotypus, US!; isotypus, NY! — Leptoglottis diffusa (Rose) Britton & Rose, N. Amer. Fl. 23(3): 141. 1928.—Maintained in specific rank by McVaugh, 1987: 244, fig. 246 (pod).

    (?) Mimosa geminata DeCandolle, Prodr. 2: 427. 1825.—"... in Americae borealis ora occidentali... (fl. mex. ic. ined.)."—Lectotypus, a colored drawing, No. 1884 of the Real Expedition in the Sessé & Mociño archive at Hunt Library, Pittsburgh! A less complete drawing in the same collection (no. 1867) appears to be conspecific. Slides of both at NY! — Bentham (1876: 634) saw only a "very rude" copy of the original, and thought it might represent a species allied to M. fragrans (=M. borealis A. Gray). In leaf-formula the drawing agrees also with var. quadrivalvis, but the locality on the west coast, which DeCandolle presumably learned from Mociño himself at Geneva, points to var. diffusa. The drawing cannot depict any known Mimosa other than M. quadrivalvis sens. lat., even though the idiosyncratic fruit of Schrankia is lacking.

    Vegetatively intermediate between the two preceding, the stems strongly angulate or not, the lfts in size and outline more often like those of var.jaliscensis; leaf-formula ii-iii/12-22; pod ± 5-12 cm long, the replum 2-5.5 mm, the valves ± 1.5-2 mm wide, all either unarmed or remotely short-aculeate.

    In thickets or in open places within deciduous woodland and palm-forest, sometimes on rocky sea-shores, below (?) 400 m, scattered along the Pacific lowlands of Mexico from Sinaloa to Colima.

    I have not found any certain way of distinguishing this taxon in the flowering condition, and am doubtful whether the nearly unarmed fruit is reliably diagnostic.