Field observations in the state reveal that Ceratophyllum demersum L. is a much more common plant than our records show. Gates (1940) lists the plant from eight scattered counties. The writer has, however, found the species in many Kansas counties and feels certain that it occurs throughout the state in suitable habitats. The species was observed to exhibit striking variations which led to the present study. Fernald (1950) notes that C. demersum is variable and in need of careful collecting and study. Jones (1931) made a study of the species and suggested that of the 35 species proposed for Ceratophyllum only two be recognized; C. demersum and C. submersum. Muenscher (1940) studied Ceratophyllum in eastern North America and recognized two species; C. demersum and C. echinatum. Most of the literature pertaining to Ceratophyllum indicates that much variation exists in the genus. Since much variation had been noted in Kansas Ceratophyllum it was decided to study the plants utilizing the mass collection technique. Mass collections were made from four sources as follows: Lakeview, Douglas County; Miami County, State Lake; Garnett Lake, Anderson County and Elks Lake, Neosho County. These collections were made in the fall of 1950.