A study of the distribution of certain members of the Saprolegniales

Abstract

The distribution of members of the Saprolegniales in twenty two natural waters, ranging in pH. from 3.6 to 8.0, throughout the United Kingdom during the period October 1956 to April 1958 is described. The method of isolation and the standardised sampling technique are fully explained. The twenty seven species collected are shown to be distributed according to the hydrogen ion concentration of the waters in which they occur. It is possible to arrange them in three main groups. There is a distinct seasonal variation in occurence of the species in those waters which were sampled at regular intervals and it is possible to distinguish "summer" and 'winter" species. The results of a study on growth and reproduction of certain selected species in pure culture and their bearing; on the distribution pattern is discussed.