Growth and development of Rhodymenia ardissonei J. Feldmann (Rhodymeniales, Rhodymeniaceae). - Rhodymenia ardissoneispores give rise in culture to a disc from which the young fronds develop. The annual development of this species in the world includes passage through different forms, among which the winter one is similar toRhodymenia phylloidesL'Hardy-Halos (1970); the autumnal forms is that described by Maggs& Guiry(1982) from Ireland asRhodymeniasp. on the coasts of Brittany and Ireland.