A preliminary study of Lemanea in western North America

Lemanea from both Europe and America is being studied to determine whether the representatives from the two continents are distinct, and whether there are undescribed species to be recognized particularly for American forms. The two subgenera, Eulemanea and Sacheria, are round on both continents (4). Occasionally plants of both the subgenera have been collected growing close together in the same stream (5, 6), but there are no indications that hybridization takes place. Several hundred specimens of Lemanea have been studied by the writer and in no case have any plants been discovered which could be considered as intermediate between Eulemanea and Sacheria