The genus Polysiphonia Grev. has a wide circunscription and is heterogeneous in vegetative and reproductive features. This paper presents a detailed study of the genus Polysiphonia sensu lato occurring at São Paulo and Espirito Santo States, Brazil, and an assessment of its morphological characteristics taking into consideration the recent taxonomic criteria, which led to the subdivision of that genus in Polysiphonia and Neosiphonia M.-S. Kim & I.K. Lee. In the present paper five species of Polysiphonia and six species of Neosiphonia were studied. Neosiphonia ferulacea (Suhr ex J. Agardh) S.M. Guim. & M.T. Fujii, N. gorgoniae (Harv.) S.M. Guim. & M.T. Fujii and N. tepida (Hollenb.) S.M. Guim. & M.T. Fujii are proposed as new combinations. Neosiphonia harveyi (Bailey) M.-S. Kim, H.-G. Choi, Guiry & G.W. Saunders is referred for the first time to the South Atlantic. This represents an uncommon occurrence since this species is considered member of the cold temperate North Atlantic flora and most of the species of Polysiphonia sensu lato so far described to Brazil have been associated to the tropical and subtropical conditions.
Ceramiales; Neosiphonia; Polysiphonia; Rhodophyta; taxonomy
