Four New Species of Solanum section Erythrotrichum (Solanaceae) from Brazil and Peru, and a Key to the Species of the Section

During a revision of Solanum section Erythrotrichum, four species, two from Brazil and two from Peru, were recognized as new and are described here. Solanum absconditum, from northeastern and northern Brazil, is similar to S. paludosum. It differs in its cordate to cordate-lanceolate, acuminate, and weakly bicolorous leaf blades that are yellowish to ferruginous above, the corolla tube 4–6 mm long, and the epicarp with stipitate-stellate trichomes. Solanum eitenii, from the “cerrado” of Maranhão, Brazil, resembles both S. decompositiflorum and S. rhytidoandrum, from which it can be distinguished by its long and pendent inflorescence and its calyx with a very short tube and oblanceolate lobes. Solanum megaspermum, from Peru, has similarities with S. mesopliarthrum, from which it differs by the triangular and very short calyx lobes (1.5–2 mm) and the scabrous and deciduous indumentum with somewhat stiff porrect-stellate trichomes. Solanum urubambaense from Cuzco, Peru, is similar to the Bolivian S. abutilifolium, but differs by its oblong-lanceolate anthers, strigose ovary, and trichomes with a reduced central ray. The species are described, illustrated and compared with similar species; commentaries on their affinities and distribution are also included. A key to the species of the section Erythrotrichum is provided.