EXTRACELLULAR INVESTMENTS IN BLUE‐GREEN ALGAE WITH PARTICULAR EMPHASIS ON THE GENUS <i>NOSTOC</i>¹

Abstract

SUMMARY The investments of a wide variety of blue‐green algae were examined. Many strains formed diffuse slime layers that were unnoticed unless mounted in India ink. Slime occurred in species with and without readily detectable sheaths. The extracellular integument type seemed consistent within strains, although the extent often varied with culture conditions. Experiments with NOSTOC on agar plates indicated that motility was inversely related to the amount of slime present. Some aspects of behavior were related to the nature of an alga's investment.