A New Species of Mimosa L. (Leguminosae: Mimosoideae) Endemic to the Chapada Diamantina, Bahia, Brazil

Abstract

Slender, diffuse herb to subshrub, 35 40(150) cm, profusely branched at the base from a xylopodium of 20 30 cm, the stems virgate, prominently ribbed, remotely leafy, and with the petioles persistent after the rhachis and pinnae have fallen, very sparsely armed with short, rather obscure, retrorse aculei (these lacking altogether on some specimens) the whole plant glabrous except for sparsely ciliate stipules, pulvinules, fruits and rarely the tip of the corolla lobes, and reddish short to long-stalked glandular trichomes sparsely and evenly distributed on the branches, leaf-stalks, peduncles, stipule margins, bracts and calyces. Stipules 1.2 2 x 0.2 0.4 mm, persistent, rigid, linear to setiform. Leaves with petiole dorsiventrally compressed, 3-ribbed, 0.3 0.8 mm wide, varying in length from 2.5 3.2 cm on the distal leaves and to 5 cm long on the basal ones, these usually lacking leaflets but with the petiole persistent, greenish and probably photosynthesising, apex with a deltoid seta c. 0.6 mm long, positioned abaxially; a subulate spicule between the single, very rarely two (noted on some duplicates of Lewis et al. CFCR 7392) pairs of pinnae; rhachis of pinnae 4.5 6.5 mm long, the longer interfoliolar segments 0.6 1 mm; leaflets in 45 pairs, oblong to oblong-oblanceolate, base asymmetric, apex broadly acute, the distal pair 3 4 x 1 1.5 mm, the immersed midrib scarsely visible, the first pair 1 2 mm distant from the deltate to cone-shaped c. 0.5 mm long paraphyllidia. Peduncles (10 -)13 16 mm long, compressed, flowering heads (excluding expanded