Coefficient of Conservatism:
Coefficient of Wetness:
R. W. Smith
A European species, first collected in 1968 in Berrien Co. and in 1970 in Oakland Co.
The corollas in both our species are dark purplish, but they run toward black in V. nigrum and tend to be somewhat paler in V. rossicum, which also has longer corolla lobes (at least twice as long as broad) and only half as many chromosomes. East of Michigan, this species has become a terrible invasive; it should be stamped out wherever observed.
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 13, 2017. http://www.michiganflora.net/species.aspx?id=168.