Vegetative and reproductive morphology of the type species of Gloiocladia, G-furcata (Faucheaceae, Rhodophyta)

摘要

The type species of Gloiocladia, G. furcata, is described in detail, and its characters are compared with those of other species currently accepted in Gloiocladia. The presence of a subcortex of ovoid, angular or stellate cells, connected by secondary pit connections to form a network parallel to the thallus surface, is confirmed. Female reproductive structures and postfertilization stages are described for the first time. Plants are procarpic, with the 3-celled carpogonial branch and two-celled auxiliary cell branch borne on a cortical cell that acts as supporting cell. The auxiliary cell contains a large proteinaceous inclusion. After fertilisation cells of the carpogonial branch fuse and connect to the auxiliary cell. The auxiliary cell divides into a primary gonimoblast cell that contains the proteinaceous inclusion and a lower auxiliary cell. A fusion cell between the auxiliary mother cell, the lower auxiliary cell and adjacent vegetative cells is formed. Gonimoblasts arising from the primary gonimoblast cell produce several erect projections bearing lobes of ovoid carposporangia. Basal nutritive cells are present, with erect persistent filaments (= tela arachnoidea) surrounding the fertilised procarp and the gonimoblast. Ostiolate cystocarps, with or without horns, arise on branch margins. Spermatangia remain unknown. Tetrasporangia are grouped in slightly raised nemathecia. In the family Faucheaceae, the presence of a subcortex in all individuals and the presence of basal nutritive tissue with erect persistent filaments in fertile female thalli are confirmed to be important taxonomic characters. These observations support the proposal of Norris (1991) to include Gloioderma in Gloiocladia but do not clarify the relationship between Gloiocladia and Fauchea.