Scirpus atrocinctus Fernald
Common Name: WOOL-GRASS
Synonym: Scirpus cyperinus
Coefficient of Conservatism: 5
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt P-Sedge

Included in S. cyperinus in Michigan Flora.

Wet meadows, bogs, lake shores and stream banks, ditches, wet shrub thickets, openings in swamps, rock crevices along Lake Superior. Usually in acidic sandy, gravelly, or peaty soils.

The Scirpus cyperinus complex, including in Michigan this species, S. cyperinus, and S. pedicellatus, is often regarded as one highly variable species. Distinguishing the species can be difficult and a few specimens appear intermediate and may be hybrids. Collectively they prefer acidic sites and sandy soils, less commonly occurring in fens or other more calcareous habitats.

Scirpus atrocinctus is a common, slender species, frequent in northern Michigan. Distinctly earlier blooming and fruiting than the other two species of the S. cyperinus complex, often with inflorescences fully expanded and maturing fruit by late June, even in the Upper Peninsula, and achenes ripe by late July.


Alcona County
Alger County
Alpena County
Arenac County
Baraga County
Cheboygan County
Chippewa County
Clare County
Crawford County
Delta County
Emmet County
Gladwin County
Gogebic County
Houghton County
Iron County
Keweenaw County
    Including Isle Royale
Leelanau County
    Only on Manitou Islands
Luce County
Mackinac County
Marquette County
Mecosta County
Midland County
Ontonagon County
Roscommon County
Schoolcraft County


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. July 27, 2021.