33. Senna obtusifolia (Linnaeus 1753: 377) H.S.Irwin & Barneby (1982: 252)

Subshrubs, branches glabrous, inermous. Nectary rachis, stipitate. Stipules lateral, acicular. Leaves paripinnate, 6– foliolate, leaflets opposite, obovate, venation brochidodromous, translucid punctuation absent. Inflorescence raceme, axillary. Flowers pedicillate, zygomorphic, diplostemonous; calyx dialysepalous, sepals 5, corolla dialypetalous, yellow, petals 5; androecium dialystaminous, heterodinamous, anthers poricidal; ovary superior, stipitate, pluriovulate. Fruit legume, sessile, linear, cylindric, margin straight, epicarp glabrous, brown. Seeds trapezoid, plane, coat brown, hilum basal.

Examined material:— BRAZIL. Paraíba: Maturéia, Pico do Jabre, 900 m elev., 14 August 2019, fl., Aureliana Gomes 356 (JPB).

Distribution and ecology: — The species is found in all regions of Brazil, associated with all phytogeographic domains and is found in disturbed areas, altitude fields, seasonal forest, costal forest and rocky outcrops (BFG 2018, Flora do Brasil 2020). In the study area, it was collected at the edge of the fragment, at 900 m.

Phenology:— Registered with flowers in August.

Taxonomic discussion:— Senna obtusifolia can be recognized, mainly, by the subshrubby habit, 6–leaflet leaves with nectary stipitate in the raque, axillary raceme, yellow corolla flowers and by the vegetable type fruit. Among the Senna species in the studied area, it was the only one that presented 6–foliolate leaves.