Reproductive morphology and development of the cystocarp inCurdiea flabellataChapman (Gracilariales, Rhodophyta)

Abstract

Abstract Based on features of the reproductive morphology in Curdiea flabellata from New Zealand, Curdiea is a distinct genus within the Gracilariaceae. Diagnostic are the complete absence of sterile gonimoblast tissue within the cystocarp; early cytological modification of the inner pericarp; an extensive network of secondary fusions between carposporophytic and gametophytic tissues in which gonimoblast cells fuse onto inner pericarp cells, followed by further fusions of cells in the floor of the cystocarp around existing pit-connections; fusion of gonimoblast cells directly with the fusion cell around primary pit-connections; organisation of all but the most basal gonimoblast cells into long chains; basipetal development of the small carposporangia; production of tetrasporangia in nemathecia. The functional morphology of the nutritive tissue of cystocarps is briefly reviewed in other genera of the Gracilariaceae.