Nasturtium officinale W. T. Aiton
Common Name: WATERCRESS
Coefficient of Conservatism: 4
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt P-Forb

Nasturtium officinale A. A. Reznicek

Margins of rivers and streams; ditches; seepy places and brooks in forests and cedar swamps, especially in cold spring-fed waters; also in sedgy tamarack swamps. Native of the Northern Hemisphere, presumably including Michigan, but also naturalized in North America beyond its native range according to Al-Shehbaz & Price (1998). The oldest collection seen was from Washtenaw Co. in 1859. This species is diploid, and has somewhat shorter fruits mostly 1.3–1.8 cm long, while in the tetraploid N. microphyllum, the more slender fruits tend to be longer, ca. 1.7–2.6 cm, and often on somewhat longer pedicels giving a more graceful look to the plant. A sterile triploid hybrid between them is known (N. ×sterile (Airy Shaw) Oefel.), which can propagate vegetatively; collections from Alpena, Jackson, and St. Clair Cos. appear to be this hybrid.

Locations

Allegan County
Antrim County
Barry County
Berrien County
Cass County
Crawford County
Grand Traverse County
Hillsdale County
Ionia County
Iosco County
Jackson County
Kalamazoo County
Kent County
Lake County
Lenawee County
Livingston County
Mackinac County
    Including Bois Blanc, Mackinac, Round Islands
Marquette County
Monroe County
Muskegon County
Newaygo County
Ottawa County
Saginaw County
Van Buren County
Washtenaw County
Wayne County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 17, 2017. http://michiganflora.net/species.aspx?id=670.