The rare planktonic diatomEunotia zasuminensisin Canada

摘要

The planktonic diatomEunotia zasuminensis(Cab.) Kouml;rner is reported from eight locations in Ontario, Canada. It is previously known from only four other localities in Europe and Africa and from two rivers in the U.S.A. The taxonomy ofE. zasuminensisis discussed relative to similar species. Observations on the rudimentary raphe in this species emphasize its proper taxonomic position within the Eunotiales. The distribution ofE. zasuminensisseems to be controlled by its apparent preference for slightly acidic or dystrophic waters.