Chamaecrista rufa var. rufa

Commonly suffrutescent, rarely to 2 m, highly variable in length, density and orientation of vesture (as described for the whole species); gland trumpet- or tack-shaped, less often claviform, (0.4-)0.5-l(-1.2) x (0.35-)0.4-0.8(-l.l) mm; longer lfts to 6-13 x 1.2-2.2(-2.6) mm; otherwise as given in key.—Collections: 58.

Openings or clearings in pine-oak and more mesic or wet tropical woodlands, disturbed thickets, and becoming an abundant colonial weed of roadsides, pastures, and milpa, (300-)870-1800, perhaps locally to 2500 m, common on the Gulf slope of Sa. Madre Oriental in Mexico from s.-w. Tamaulipas to Puebla, thence s. interruptedly through highland Oaxaca and Chiapas to Guatemala (Huehuetenango) and n.-w. Honduras (Cortés); apparently disjunct in s. Costa Rica (Puntarenas), and collected once (Bourgeau in 1865) on the Mexican Plateau in Distrito Federal, perhaps introduced.—Fl. V-III.

The feature of var. rufa most directly and strikingly seen as variable is the vesture of stems and leaf-stalks, which may be simply incurved-puberulent (C. rufa, sens. str.), simply setose (Ch. jalapensis, sens, str.) or a variably proportioned mixture of the two (e.g. G. L. Smith 1548, p.p. NY). These variants occur within a few kilometers of each other on the Gulf slope of Mt. Orizaba, sometimes together, and are of random occurrence outside of Veracruz, both north and southward. Independently of pubescence the petiolar gland varies substantially in size and in elevation of its stipe, which varies from subfiliform to coarsely club-shaped. In the material examined we have detected no major separation of self-perpetuating races.

First collected in Mexico in late XVIII century, probably by Sessé and collaborators (Nueva España, hb. Pavon., BM, which probably = Cassia chamaecrista Sessé & Mociño, l.c. supra).