Abstract: The phenology of Batrachospermum acuatum was studied. The specimens were collected four times from January 2005 to October 2005(one sampling per season). The air temperature, water temperature, current velocity, pH, dissolved oxygen, specific conductance were monitored at every sampling time. Ten main morphological characteristics of B.acuatum were observed and measured under the microscope. The results showed that all the environmental factors had seasonal patterns to different extent and some of the morphological characteristics had significant seasonal fluctuations, indicating the differences in their seasonality. B.acuatum grew well in spring but not so good in summer. The relationship results showed that despite the development of B.acuatum was affected by environmental factors to some extent, the key factor was its own biological rhythm.

Key words: Batrachospermum acuatum, China, environmental factors, seasonal dynamics, Xin&rsquo, an Spring