Euphorbia setosa (Boiss.) Müller Argoviensis (1874: 672)

Silva, Otávio Luis Marques Da, Cordeiro, Inês & Caruzo, Maria Beatriz Rossi, 2014, Synopsis of Euphorbia (Euphorbiaceae) in the state of São Paulo, Brazil, Phytotaxa 181 (4), pp. 193-215 : 207

21. Euphorbia setosa (Boiss.) Müller Argoviensis (1874: 672) ( Fig. 7A–C ).

Euphorbia selloi var. setosa Boissier (1862: 50) . Lectotype (designated here): — BRASIL. Goiás: in campis incultis, N.T. Lund s.n. (G00311064!); remaining syntypes: same locality, L. Riedel s.n. (LE); Tijuco, F. Sellow s.n. (not located); Minas Gerais: in cacumine montis Urubu, J.B.E. Pohl 1674 (W0031069!).

Distribution and habitat:— Euphorbia setosa is endemic to Brazil (Distrito Federal, Goiás, Minas Gerais and São Paulo). In the State of São Paulo it occurs in cerrado vegetation.

Representative Specimen:— BRAZIL. São Paulo: Pedregulho , 06 November 1997, W. Marcondes-Ferreira et al. 1555 (SP, SPSF) .

Taxonomic notes:— Euphorbia setosa may be easily identified among the species in the state of São Paulo by its cyathial glands with erect and pubescent petaloid appendages, while others species’ petaloid appendages are always patent and glabrate. By having cyathia arranged in capitate dichasia and hirsute stems, Euphorbia setosa may be misidentified as E. hirta or E. ophthalmica , but these species may be distinguished by their lanceolate blades, cladodromous venation, entire leaf margin (vs. elliptic blades, actinodromous venation, serrate leaf margin in E. hirta and E. ophthalmica ), number of flowers in each staminate cymule (10–12 in E. setosa vs. 1–2 in E. hirta and E. ophthalmica ), and alveolate seeds coat (vs. seeds with transverse ridges in E. hirta and E. ophthalmica ).

The species is commonly misidentified as Euphorbia selloi (Klotzsch & Garcke in Klotzsch 1860: 32) Boissier (1862: 50), which is in fact very similar to it. However, it can be distinguished from it by its cyathial glands with erect and pubescent petaloid appendages (vs. patent and glabrous in E. selloi ). Besides this, the geographic distribution is distinct between both species: E. setosa occurs in central–southeastern Brazil and E. selloi occurs in southern Brazil, northern Argentina and Uruguay ( Simmons & Hayden 1997).

Figures

FIGURE 7. A–C: Euphorbia setosa. A. habit, B. stem, C. branch with cyathia. D–E: Euphorbia thymifolia. D. habit, E. branch with cyathia. F–H: Euphorbia zonosperma. F. habit, G. leaf, H. cyathia. Photos:A–E: O.L.M. Silva, F–H: M. Pastore.