A comparative study of Gomontia polyrhiza and Chlorojackia pachyclados gen. et sp. nov. (Chlorophyta)

Culture studies of Gomontia polyrhiza from Canada and Denmark verify the presence of this species in the two countries and confirm the life history. Chlorojackia pachyclados gen. et sp. nov. has some features in common with Gomontia, but the presence of a parenchymatous thallus, vegetative cells with lobed chloroplast, different pattern of germination of the unicellular stage, and inability to grow into a calcareous substrate distinguish the new entity from Gomontia. In culture, C. pachyclados has a heteromorphic life history, with production of unicellular and parenchymatous thalli influenced to some extent by temperature.