Cultured Aquatic Species Information Programme Gracilaria spp

Thallus erect or prostrate (decumbent), branched subdichotomously, laterally, secondly, radially or irregularly; axes and branches terete to flattened. Attached to solid substratum by a small discoid holdfast or living on sandy bottoms with part of the thallus immersed in the sand. Sometimes loose lying or floating in calm waters. Uniaxial construction but appearing multiaxial, pseudoparenchymatous with a small celled medulla.
Life history triphasic with isomorphic gametophytes and tetrasporapytes. In the genus Gracilaria, cystocarps exhibit traversing nutritive cells between the carposporophyte and the pericarp and spermataagia are in pits or conceptacles. In the genus Gracilariopsis, cystocarps lack the traversing nutritive cells and spermatangia are superficial.