Myriophyllum alterniflorum DC.
Common Name: ALTERNATE-LEAVED WATER-MILFOIL
Coefficient of Conservatism: 10
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt P-Forb
Status: SC
Myriophyllum alterniflorum submersed G. E. Crow submersed

A northern species primarily known from softwater lakes and bays of Lake Superior and the St. Mary’s River.

This is a neat, slender plant, with rather dense very short leaves on an often sinuous, much-branched stem ca. 0.3–1 (–1.5) mm thick.

The St. Clair Co. record seems quite out of line, and was not mapped in Michigan Flora, but there seems to be no evidence of mis-labeling. The plant is known from a few more southern station to the east and west of Michigan. 

Locations

Alger County
Baraga County
Charlevoix County
    Only on Beaver Island
Chippewa County
Gogebic County
Keweenaw County
    Including Isle Royale
Luce County
Marquette County
St. Clair County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 16, 2017. http://www.michiganflora.net/species.aspx?id=1424.