AHNFELTIOPSIS TRIQUETRIFOLIA SP. NOV. (GIGARTINALES, RHODOPHYTA) FROMJAPAN

The marine red alga Ahnfeltiopsis friquetrifolia sp. nov. (Phyllophora ceae, Gigartinales) is described from Japan. Foliaceous unisexual game tophytes are characterized by having three-edged axes, and crustose te trasporophytes are distinguished by the following combination of featu res: tightly coalescent perithallial filaments, nemathecial sori, smal l numbers of both tetrasporangia (3 or 4) and sterile cap cells (1 or 2) in each fertile filament, and the absence of hypobasal tissue. Goni moblast filaments develop from the auxiliary cell after it has fused w ith a carpogonium. Carposporangia develop from gonimoblast cells, from medullary cells contacted by the gonimoblast filaments, and from the cells produced by such medullary cells. Mature, compact cystocarps are immersed within the medullary layer and discharge carpospores through carpostomes formed in the thickened cortex. Cultured tetrasporophytes were induced to sporulate by transfer from a long-day to a short-day regime at 20 degrees C, and one single short-day cycle was effective f or tetrasporangial induction. Tetraspore germlings gave rise to basal discs from which upright axes developed. The upright axes showed a mor phology similar to that of field-collected gametophytes, although they remained vegetative during 18 months in culture.