The ultrastructural bases of chrysophyte systematics and phylogeny

Abstract
By means of light microscopy certain main lines in chrysophyte taxonomy were demonstrated during the first half of this century. However, the increasing use of electron microscopy from the 1950s and 1960s, together with other modern methods such as pigment analysis and advanced culture techniques, have improved our knowledge considerably and have made necessary even quite fundamental changes, both as regards the delimitation of the Chrysophyceae, and as to the relationships between the various groups within this class. On the species level, electron microscopy has been especially useful as regards the silica‐scale bearing groups, and the main problems are here now to judge how small differences in scale structure really should be given taxonomic value.