Morphology and reproduction ofSynura lapponica(Synurophyceae)

Abstract

Observations with both light and electron microscopy on populations of Synura lapponica from three oligotrophic bodies of water in the region of Victoria, British Columbia, provide the first detailed description of the morphology and reproduction of the species, and the first record of the species in Canada. In typical colonies the radially organised cells were attached to a central ‘hub’ and enclosed in a colonial envelope. Embedded in the peripheral matrix of this envelope was a colonial scale case composed of a multiple layer of biradially symmetrical plate-scales. Imbricate scale cases were absent. Colony fission, colonies exhibiting cellular dimorphism, palmelloid reproductive colonies, and ‘halo’ colonies are described for the first time. The results of this study expand the current knowledge of the species, and describe several morphological features that support the affinity between S. lapponica and Tessellaria volvocina (Synurophyceae).