"s have contested for possession of the waters much as the have contended for supremacy on land, until it may be said that the dominant forage crop of our lakes, ponds, and s is to be found among the pondweeds, the s. Variety in form, adaptability to , and diversity in range have all contributed their share in giving prominence in this group and in furthering a natural resource whose propagation and control are vital factors in the economic relations of the life of inland waters."