<I>Dasya rigidula</I> (Ceramiales, Rhodophyta) in the south and southeastern brazillan coast

Abstract

This work describes, for the first time, Dasya rigidula (Kützing) Ardissone from the south and southeastern Brazil. The specimens presented irregularsubdichotomously branching; variable cortication along the thallus; ocellate apex; and stichidia with four tetrasporangia per segment. Traditionally, the species of this genus are diagnosed depending on the branching parttem, presence of ocellate apex and degree of cortication. Tenuous variations of these characteristics separate Dasya brasiliensis, D. caraibica and Dasya rigidula, and these variations have been observed among specimens of a single popu1ation ana1ysed by us. Nowadays, the number of tetrasporangia per segment of stichidia is used to diagnose species and all the taxa listed above have four, among other common characteristics. We believe that, in the Brazilian coast, they represent the sarne species and should be sinomyzed with Dasya rigidula.