Laurencia viridis sp. nov. (Ceramiales, Rhodomelaceae) from the Macaronesian Archipelagos

Abstract

Laurencia viridis sp. nov. (Ceramiales, Rhodomelaceae) is described from specimens collected around the Canary Islands and herbarium examples from Azores Islands, Madeira Islands, Salvage Islands and Cape Verde Islands. Vegetative fronds, sporophytes and gametophytes (male and female) arise from stoloniferous axes. Characteristics of this new species include the following: a distinct green colour of both vegetative and fertile plants, with pinkish apical regions; presence of secondary pit-connections between adjacent cortical cells; terete branches radially arranged; spermatangial receptacle of determinate position, cup-like and with a clear central axis; tetrasporangia in parallel abaxial rows. This species is placed in the genus Laurencia Lamouroux, subgenus Laurencia Saito, section Laurencia Saito. Ecological data are presented. We compare the L. viridis from the Macaronesian Archipelagos with the green species of Laurencia from other parts of the world.