ULTRASTRUCTURE OF<i>CHAETOCEROS MUELLERI</i>(BACILLARIOPHYCEAE): AUXOSPORE, RESTING SPORE AND VEGETATIVE CELL MORPHOLOGY¹

Abstract

ABSTRACT The structure of the frustule of auxospores, resting spores and vegetative cells of Chaetoceros muelleri Lemm. are described with LM and SEM. Vegetative frustules are relatively small and lightly silicified, are not united into filaments, and appear unornamented under LM and SEM. The setae are circular to subcircular in transverse section with spines and puncta arranged in a spiral pattern. The resting spore and auxospore frustules are more silicified than the vegetative frustules and appear unornamented under LM and SEM. The auxospores of C. muelleri were previously unknown.