OBSERVATIONS ON FILAMENT FORMATION IN MICRASTERIAS FOLIACEA (DESMIDIACEAE,CHLOROPHYTA)1

Filaments of Micrasterias foliacea Bailey were isolated from a sample of a Texas lake. Cultures were established and examined by light and scanning electron microscopy (SEM). Enzymatic removal of mucilage proved necessary to obtain well preserved cells for SEM investigation. The development of the overlapping polar lobes and the formation of the interlocking apical teeth are described. The importance of these, of mucilage and the primary wall for filament formation is discussed.