Senna rizzinii H.S. Irwin & Barneby (1982: 174–175)

Gomes, Aureliana Santos, Rodrigues, Erimágna De Morais, Moura, Débora Coelho, Melo, José Iranildo Miranda De, Ribeiro, Rayane De Tasso Moreira & Queiroz, Rubens Teixeira De, 2022, Fabaceae Lindl. in a Conservation Unit in the Semi-Arid Region of Paraíba, Brazil, Phytotaxa 555 (1), pp. 17-41 : 35-36

34. Senna rizzinii H.S. Irwin & Barneby (1982: 174–175) . ( Fig. 4g )

Shrubs scandent, branches tomentose, inermous. Nectary rachis, stipitate. Stipules lateral, acicular. Leaves paripinnate, 4–foliolate, leaflets opposite, lanceolate, venation brochidodromous, translucid punctuation absent. Inflorescence raceme, axillary, terminal. Flowers pedicillate, zygomorphic, diplostemonous; calyx dialysepalous, sepals 5, corolla dialypetalous, yellow, petals 5; androecium dialystaminous, heterodinamous, anthers poricidal; ovary superior, sessile, pluriovulate. Fruit berry, stipitate, linear, cylindric, margin straight, epicarp tomentulose, brown. Seeds obovate, plane, coat black, hilum basal.

Examined material:— BRAZIL. Paraíba: Maturéia, Pico do Jabre , 1.000 m elev., 03 May 2019, fl., Aureliana Gomes 2018 ( HACAM) .

Distribution and ecology:—It is restricted to the Northeast of Brazil (AL, BA, CE, MA, PB, PE, PI, RN, SE), associated with the phytogeographic domain of the Caatinga (Queiroz 2009; BFG 2018).

Phenology:— Registered with flowers in May.

Taxonomic discussion:— Senna rizzinii can be recognized, mainly, by the shrubby habit, inermous branches, lateral stipules, terminal raceme, zygomorphic flowers with yellow corolla and bacoid fruits. It resembles Senna macranthera morphologically, but can be distinguished by the ovate bracts in S. rizzinii vs. linear bracts in S. macranthera .

Figures

FIGURE 4. Species of Fabaceae Lindl. of the study area, Pico do Jabre State Park, Paraíba, Brazil. a Chamaecrista nictitans. b Anadenanthera colubrina. c Chamaecrista zygophylloides. d Albizia polycephala. e Senna macranthera. f Mimosa invisa. g Senna rizzinii. h Calliandra subspicata. i Enterolobium contortisiliquum. j Senna martiana. (Source: the authors).