Coefficient of Conservatism:
Coefficient of Wetness:
G. E. Crow
A South American species commonly grown in aquaria and ponds, and rarely (thus far) escaping in ponds and streams near developed settings. It is apparently able to survive winters under water and in spring fed streams, and has become established north to southern New England. First collected in Michigan in 1962, by Eldon Whiteman at the edge of a creek in Kalamazoo Co., but the record overlooked; more recently found in 2013 in Wayne Co. by D. Rayner, S. Shaw and S. Tangora. A major pest in the southern US; it should be watched to see how aggressive it will be in Michigan.
This is a striking species, quite different from all our other Myriophyllum. The flowers are born above surface of the water, like most of our species, but in the axils of fully developed dissected leaves (looking much like the submerged leaves) rather than subtended by bracts that are quite different from the submersed leaves. The species is apparently dioecious; it is not certain if both sexes are represented among Michigan plants, those few fertile are female.