Hypericum prolificum L.
Common Name: SHRUBBY ST. JOHN'S-WORT
Coefficient of Conservatism: 5
Coefficient of Wetness: 3
Wetness Index: FACU
Physiognomy: Nt Shrub

Hypericum prolificum B. S. Walters

Swamp borders, thickets, meadows, fields, roadsides, sandy open forests (oak); in drier sites generally than Hypericum kalmianum, often in successional shrubby fields. 

Flowers need to be examined carefully for the style (and capel) number. Especially in younger flowers, 2 or more of the 5 styles in Hypericum kalmianum may have not yet separated.

The North Manitou Island collection (F. Wislizenus 467 in 1886, MO) seems a little out of range; it includes a fragment of H. perforatum (the original identification) and could represent an inadvertent mixture from some other locality.

Locations

Barry County
Berrien County
Branch County
Calhoun County
Cass County
Clinton County
Eaton County
Genesee County
Hillsdale County
Ingham County
Ionia County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Lapeer County
Leelanau County
    Only on Manitou Islands
Lenawee County
Livingston County
Mecosta County
Midland County
Monroe County
Montcalm County
Newaygo County
Oakland County
Saginaw County
Shiawassee County
St. Clair County
St. Joseph 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://michiganflora.net/species.aspx?id=1466.