TAXONOMIC STUDIES ON CERAMIEAE (CERAMIALES, RHODOPHYTA) WITH PREDOMINANTLY BASIPETAL GROWTH OF CORTICATING FILAMENTS

Ceramieae, the Ceramiaceae that have corticating filaments applied on axes at junctions of monosiphonous filaments, have species in which co rticating filaments remain only at the nodes or cover the axis by grow ing mostly in an acropetal (Ceramium) or a basipetal direction (Centro ceras). Those species with mostly basipetal growth of corticating fila ments have either three or four primary corticating filaments from eac h pericentral cell. Some species having three primary corticating fila ments from each pericentral cell have two placed distally and one in a proximal position. Only acropetal growth occurs in one of the distal filaments, producing only a 2-3-celled filament. Basipetal growth occu rs on the other distal filament which may also produce a 1-few-celled acropetal filament. Only basipetal growth occurs on the proximal corti cating filament on the pericentral cell. Species with these characters are assigned to Centroceras and a new species, Centroceras corallophi loides is proposed. In addition to the typical arrangement of corticat ing filaments, it also has fasciculate male branchlets at nodes, and e xserted tetrasporangia, characters typical for Centroceras. Corallophi la Weber-van Bosse appears to have similar characters but the type spe cies, C. kleiwegii, has four corticating filaments from each pericentr al cell, two acropetal and two basipetal. It is suggested that Corallo phila be recognized as a genus distinct from both Centroceras and Cera mium and that Ceramiella Borgesen be considered synonymous with Corall ophila. Additional species with these characters are assigned to Coral lophila. The revised description of Corallophila includes species with tetrasporangia mostly covered by cortication and spermatangia on most outer corticals cells in fertile regions.