Persicaria hydropiperoides (Michx.) Small
Synonym: Polygonum hydropiperoides
Coefficient of Conservatism: 5
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt P-Forb

Polygonum hydropiperoides of Michigan Flora.

Swamps; bogs, fens, and ditches; borders of lakes, ponds, and rivers; often in shallow water.

A variable species or complex. No Michigan specimens have spreading to ascending hairs on the ocreae, said to characterize P. setacea (Baldwin) Small, though otherwise, pubescence is highly variable. Plants from throughout the state may bear on the leaves flat, plate-like, pale, easily dislodged, sparse and irregularly spaced “glands” resembling the farinosity of some Amaranthaceae. Fewer plants bear these on the perianth, which would make them referable, according to some authors, to Polygonum opelousanum Riddell var. adenocalyx Stanford; a narrow-leaved (< 1 cm) entity with a restricted distribution. However, specimens with abundant glands on the calyx (especially a few from Berrien and Cass Cos.) include narrow as well as broader (to 2 cm) leaved plants. This group clearly needs additional study in the state. The flowers of this species often appear open in the field, while in our other smartweeds the tepals generally remain closed.


Allegan County
Alpena County
Antrim County
Barry County
Bay County
Berrien County
Calhoun County
Cass County
Cheboygan County
Clare County
Clinton County
Emmet County
Gogebic County
Gratiot County
Hillsdale County
Houghton County
Huron County
Ingham County
Ionia County
Isabella County
Jackson County
Kalamazoo County
Kent County
Lake County
Lapeer County
Leelanau County
    Including Fox Islands
Lenawee County
Livingston County
Mackinac County
    Only on Bois Blanc, Mackinac, Round Islands
Macomb County
Manistee County
Marquette County
Mason County
Mecosta County
Missaukee County
Monroe County
Montcalm County
Muskegon County
Newaygo County
Oakland County
Oceana County
Ontonagon County
Ottawa County
Presque Isle County
Roscommon County
Sanilac County
Shiawassee County
St. Clair County
St. Joseph County
Van Buren County
Washtenaw County
Wayne County


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. June 29, 2022.