The fine structure of Synura sphagnicola (Korsh.) Korsh. (Chrysophyceae)

S. sphagnicola resembles other species of Synura previously described by electron microscopy in most features of structure but differs in possessing pyrenoids and up to five cylindrical stacks of smooth cisternae which occur between the pyrenoids and leucosin vesicles. Each stack is surrounded by a tubular cisterna which bears ribosomes on its distal face but there are no clear permanent connections between this and the chloroplast ER. Other features apparently unique to this species previously known from light microscopy are described. These include the axial position of the chloroplasts; the peripheral position of the leucosin vesicles; and the loose attachment of the scales. The structure of the body scales is described for the first time from sections. The flagellar scales are formed in the swollen edges of the Golgi cisternae and appear to pass to the cell surface in large vesicles.