Heterococcus endolithicus sp. nov. (Xanthophyceae) and other terrestrial Heterococcus species from Antarctica: morphological changes during life history and response to temperature

Strains of Heterococcus endolithicus sp. nov., H. pleurococcoides Pitschmann, H. caespitosus Vischer, and H. protonematoides Vischer isolated from terrestrial habitats in Antarctica were studied in culture. Morphology of the algae changes with stage in life history. The characteristic branching patterns are not present in very young or old cultures. Filament formation is suppressed when cultures are grown outside their optimal temperature range.