Abstract
Summary. The mineral content of Elodea canadensis and Lagarosiphon major growing in two lakes near Rotorua showed seasonal variation and was influenced by the nutrient status of the water. Large quantities of L. major occur in Lake Rotorua and the average mineral content found was 3·9% N, 0·5% P, 2·6% K and 0·7% Mg (dry‐weight basis), a level which indicates potential commercial value.Variations de la composition chimique de deux mauvaises herbes aquatiques des lacs de Nouvelle‐Zélande