| Abstract: | Five taxa of Chaetoceros occur in inland waters of North America. These most commonly occur in waters with elevated total dissolved solids in arid regions of the western United States and Canada. Chaetoceros amanita Cleve-Euler is characterized by consistently forming relatively long chains of cells and having very spinose primary resting spore valves. Chaetoceros elmorei Boyer also forms long chains of cells which are connected by evident valvar processes; spores are nearly always smooth. Chaetoceros muelleri Lemm. may form short chains with processes between sibling valves, but also produces solitary cells lacking processes. Chaetoceros muelleri var. subsalsum (Lemm.)Johansen et Rushforth is similar to the nominate but never produces cells with Processes. Both of the C. muelleri varieties produce spores with smooth primary valves. Chaetoceros simplex Ostenfeld is characterized by a noncolonial habit, cells lacking processes and the production of resting spores with warty to some what spinose primary valves. |
