Studies in the Bangioideae III. The Life-history of Porphyra umbilicalis (L.) Kütz. var. lociniata (Lightf.) J. Ag.1

Abstract

As the first step in an investigation of the life-history of Porphyra umbilicalis (L.) Kütz. var. laciniata (Lightf.) J. Ag., spores which have originated as a result of the repeated division of the mother-cells have been germinated. When grown on glass their method of germination and growth agrees with that described by previous investigators, but when germinated on sterile shell the germ-tubes penetrate the shell and develop into growths identical with Conchocelis rosea Batters. This ‘species’, therefore, is a phase in the life-history of P. umbilicalis var. laciniata and not an autonomous species. The development of the ‘Conchocelis’-phase in culture is described and also the formation of fertile cell-rows and ‘plantlets’. Until the significance of these structures is understood and a cytological investigation completed, the relationship of the intertidal leafy Porphyra-thallua to the filamentous, shell-inhabiting, deep-water Conchocelis cannot be expressed in the terms usually employed to denote the various phases of the life-histories of algae.