This paper presents a taxonomic study of the genera Chaetomorpha and Rhizoclonium occurring in the littoral of Bahia. The species were defined based on habit, presence or absence of lateral rhizoids, basal cell type, shape and cells dimensions. The presence of crystalline inclusions in cells was also verified. It were identified nine species, seven to the genus Chaetomorpha (C. aerea (Dillwyn) Kütz., C. antennina (Bory) Kütz., C. brachygona Harv., C. clavata Kütz., C. crassa (C. Agardh) Kütz., C. minima Collins & Herv. and C. nodosa Kütz.) and two to the genus Rhizoclonium (R. africanum Kütz. and R. riparium (Roth) Kütz. ex Harv.). Chaetomorpha crassa, C. minima and C. nodosa are new additions to the Northeastern of Brazil and C. aerea, C. clavata and R. africanum are additions to the Bahia. Three crystals types were found: 1. clusters of fine needle-shaped of silica crystals presents in C. aerea, C. antennina, C. brachygona, C. clavata and C. crassa; 2. octahedral of calcium oxalate crystals found in C. antennina and C. clavata and, 3. globular aggregates of cone-shaped calcium carbonate crystals observed in C. clavata. Fertile thallus of C. antennina, C. clavata, C. nodosa, R. africanum and R. riparium are being illustrated for the first time for the Brazilian coast. The vegetative and reproductive structures are described in detail and a comparison with similar species is provided.
Bahia; Chaetomorpha; Chlorophyta; crystalline inclusions; Rhizoclonium
