Ash content of macrophytes from Chautauqua Lake

62 ash content determinations were made on 5 predominant macrophytes from Chautautauqua Lake, NY. Intraspecific seasonal variations (May /July-Aug), examined for Myriophyllum sp only, were not statistically significant. However, many significant interspecific differences were noted; ash content in Aacharis canadenis and Vallisneria americana were significantly greater than in Potamogeton richardosonii and P. crispus, while that of Myriophyllum sp was intermediate. A review of determinations on similar taxa from other waters revealed that each content tended to increase with alkalinity in the Potamogetaonaceae and Halgoridaceae (Myriophyllum sp), but not in the Hydrocharitaceae (Anacharis sp, Vallisneria sp).