Monographs Details: Mimosa setosa subsp. urbica Barneby
Authors:Rupert C. Barneby
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.
Description:Subspecies Description - Weakly frutescent, attaining 2 m but often smaller, the stems and lf-axes yellowish-setose and minutely villosulous (sometimes only on ventral angles of lf-stk), eglandular; pinnae variable in number (4-23-jug.), the longer ones (5-)6- 12 cm and the longer interfoliolar segments 2-3.5 mm; floral bracts 6-8 x 0.8-1.2 mm, surpassing the subtended fl by (1-) 1.5-2.5 mm; corolla lobes charged dorsally with scattered pallid tubercles capped or not with a fine setula and often a few short claviform eglandular (randomly gland-tipped) trichomes; pods villosulous overall and thinly yellow-hispid eglandular.
The subsp. urbica apparently replaces subsp. setosa over much of the Paranoá basin in the Federal District. It may be recognized by very long floral bracts, by the lack (complete or almost so) of glandular trichomes or viscidity, and by the pinnae on the average longer and composed of larger, more distant leaflets. The subspecies occurs in two forms, var. urbica and the possibly juvenile var. urbana, distinguished (as given above, in key) by leaf-formula.