Distribución y variación morfológica de Amphiroa beauvoisii (Corallinales, Rhodophyta) en México

Several samples of Amphiroa beauvoisii (Corallinales, Rhodophyta) were collected in different localities along the Pacific and Caribbean coasts of Mexican from 1994 to 2007. An extensive review of Amphiroa beauvoisii recorded from Mexico was carried out. Specimens of different herbaria were examined to determine its geographic distribution, as well as morphological and reproductive data for this taxon. Analysis of this information showed that this species is distributed along the Pacific coast from Islas Coronados, Baja California to La Ventosa, Oaxaca. A. beauvoisii is frequent in the Gulf of California and Jalisco, Guerrero and Oaxaca, while on the Atlantic coast it is rare and we only found it on coralline reefs of Yucatán and Quintana Roo. Morphological variation, reproductive stage, and distinctive characteristics of this taxon are included. A. beauvoisii is an extremely variable species; the tetrasporangial and bisporangial thalli are more common, more branched and taller that the gametangial plants. We found gametangial and tetrasporangial plants on the Pacific coast and only tetrasporangial plants in the Caribbean. Male and female plants of A. beauvoisii are described for the first time from Mexican populations.