Most of the known species of waterlily (Nymphaea Sm.) are extremely variable. The student feels obliged to recognize certain extreme forms as species. These are often restricted geographically. But where their habitats are connected by continuous land areas, the intermediate country is usually populated by a series of waterlilies which grade insensibly from one extreme to the other. The commoner white waterlilies of North America illustrate these conditions.
Proceedings of the Iowa Academy of Science
©1916 Iowa Academy of Science, Inc.
Conard, Henry S.
"The White Waterlily of Iowa,"
Proceedings of the Iowa Academy of Science, 23(1), 621-623.
Available at: https://scholarworks.uni.edu/pias/vol23/iss1/67