Ranunculus hispidus Michx.
Common Name: SWAMP BUTTERCUP
Coefficient of Conservatism: 5
Coefficient of Wetness: 0
Wetness Index: FAC
Physiognomy: Nt P-Forb

Variety hispidus is very local in the southernmost Lower Peninsula, from Monroe Co. to Kalamazoo Co.; it grows in moist to dry upland places (oak forests, sandy knolls, etc.). The other two, more widespread varieties have practically the same habitats and may indeed grow together; they are characteristic of wet areas in forests and thickets along streams, ponds, and lakes, as well as ravines and in deciduous or cedar swamps.

This is an extremely variable species, with the lateral leaflets (as well as the terminal one) definitely petiolulate, at least the upper ones ± sharply toothed, and the roots, even if slightly thickened, long and not tuberous. We recognize three varieties:

(a) Variety hispidus barely enters southernmost Michigan and is a small erect plant, not producing trailing shoots; the petals are less than 1 cm long and the achenes are only narrowly margined.

(b) Variety caricetorum (Greene) T. Duncan occurs throughout the state and is a large coarse often very pubescent plant (with twice the chromosomes of the other varieties), producing trailing shoots which often root (and which can be seen developing from the base of the plant early in the season); the flowers are the largest in this variety, the petals usually over 1 cm long and sometimes nearly 2 cm.

(c) Variety nitidus (Elliott) T. Duncan, found in the southern half or two-thirds of the Lower Peninsula, somewhat similar to var. hispidus in small stature and often confused with it, but characteristic of moist habitats and with trailing shoots, as in var. caricetorum, from which it differs in more broadly winged achenes, petals seldom much over 1 cm long, and often less pubescence. Ranunculus septentrionalis Poir. is a name widely used for var. caricetorum but actually applying to var. nitidus.

Locations

Alcona County
Alger County
Allegan County
Antrim County
Arenac County
Baraga County
Barry County
Bay County
Benzie County
Berrien County
Calhoun County
Cass County
Charlevoix County
    Including Beaver Island
Cheboygan County
Chippewa County
Clare County
Clinton County
Crawford County
Delta County
Eaton County
Emmet County
Genesee County
Gogebic County
Grand Traverse County
Gratiot County
Hillsdale County
Houghton County
Ingham County
Ionia County
Iosco County
Isabella County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Keweenaw County
    Including Isle Royale
Lake County
Lapeer County
Leelanau County
    Including Fox Islands
Lenawee County
Livingston County
Luce County
Mackinac County
    Including Bois Blanc, Mackinac, Round Islands
Macomb County
Manistee County
Marquette County
Mecosta County
Menominee County
Midland County
Monroe County
Montcalm County
Muskegon County
Newaygo County
Oakland County
Oceana County
Ontonagon County
Osceola County
Oscoda County
Otsego County
Ottawa County
Presque Isle County
Saginaw County
Sanilac County
Shiawassee County
St. Clair County
St. Joseph County
Tuscola 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 11, 2017. http://www.michiganflora.net/species.aspx?id=2391.