Nomenclature of Sessea corymbiflora (Solanaceae) and Its Occurrence in Venezuela

Abstract

The occurrence of Sessea corymbiflora in Venezuela is reported for the first time. It is presented here as a new species and an additional genus for the solanaceous flora of Venezuela. A description and illustration of the species are provided. The contorted nomenclature of S. corymbiflora is discussed, and the names S. corymbosa and S. atrovirens, in current use as referring to distinct entities, are reduced to synonymy. Sessea, a poorly known genus mainly of Andean regions of South America, was hitherto unknown in Venezuela. The plants and their flowers closely resemble those of the much larger genus Cestrum, but the fruits and seeds are quite distinctive. The species reported here was discovered among specimens of Cestrum while the authors worked on a taxonomic revision of this genus. Sessea was first described by Ruiz & Pav6n in their series of works on the flora of Peru and Chile. The genus was described and illustrated in the Prodromus (1794), two species were described in the Systema Vegetabilium (1798), and these were illustrated in the Flora Peruvianae et Chilensis (1799). The species reported here, S. corymbifora Taylor & Phillips, was described two decades later from material collected in Colombia. The larger genus Cestrum, which is similar to Sessea, was described by Linnaeus in 1753. Besides the original descriptions noted and other minor comments, the genus has had overall consideration by only three botanists, Bitter (1922), Francey(1933, 1934, 1935: 46-51), and Toledo (1941). Bitter arranged species into five series, and Francey and Toledo provided keys to the species published up to the time of their works. Diversity is apparently greatest in Peru, Ecuador, and Colombia, although two species occur in Brazil, one is recorded from Haiti, and we report one from Venezuela. NOVON 3: 324-327. 1993. THE GENUS SESSEA Sessea Ruiz & Pav6n, Fl. Peruv. 21. 1794. TYPE: S. stipulata Ruiz & Pavon, (lectotype, designated by D'Arcy, Solanac. Newsl. 2(4): 30. 1986). Sesseopsis Hassler, Ann. Cons. Jard. Bot. Geneve. 20: 183. 1916. TYPE: S. vischeri (Chodat) Hassler = Sessea vischeri Chodat cf. Hunziker (1977). In traditional classifications (D'Arcy, 1991), Sessea is placed in the Solanaceae in tribe Cestreae of subfamily Cestroideae. This tribe comprises five genera. Three of these are monotypic with widely separated distributions (D'Arcy, 1992): Metternichia-Rio de Janeiro, Brazil; Tsoala-western Madagascar; and Vestia-south-central Chile. Each of these has corollas and fruit quite different from Sessea, although Vestia is most similar in overall appearance. The remaining two genera are Sessea and Cestrum. Cestrum includes over 150 species distributed throughout warm regions of the Americas, and it is the only genus in the tribe with a juicy, berry fruit that is dispersed by birds. All members of tribe Cestreae except Cestrum have a dry capsule. In Tsoala, dehiscence of the capsule is unknown, but in Sessea, Vestia, and Metternichia, the capsule is longitudinally dehiscent. Sessea corymbiflora Goudot ex Taylor & Phillips, Phil. Mag. 3: 132. 1828. TYPE: in woods near Bogota, Goudot 1 (lectotype, P; isolectotypes, K not seen, G-DC not seen, microfiche MO,