Eriophorum russeolum Fr.
Common Name: COTTON-GRASS
Coefficient of Conservatism: 10
Coefficient of Wetness: -5
Wetness Index: OBL
Physiognomy: Nt P-Sedge

Poor to rich fens near Lake Superior, especially in the wetter portions.

This is a single headed species, but very different from Eriophorum vaginatum in being a larger plant with larger heads, and colonial from long-creeping rhizomes, so the culms are scattered, not in dense tufts.

Long expected from northernmost Michigan, as it was well documented in Minnesota and Wisconsin, Eriophorum russeolum was independently discovered in 2019 by A. Graeff, R. Routledge, and J. Marr in Keweenaw and Marquette Cos. See Routledge, Graeff, & Marr (2020) for details.

Specimens lacking rhizomes can be distinguished from E. vaginatum by the prominent whitish-hyaline apical portion of the lowest (sterile) scales, and the long (ca. 0.5-0.6 mm) tapering beak on the achene. In E. vaginatum, the sterile scales are dark gray, becoming paler gray apically, but only the very tip fading to pale gray or nearly white, the overall aspect being quite dark, and the achene is abruptly contracted to a minute (ca. 0.1 mm) apiculus. Our plants are subsp. leiocarpum Novoselova, with whitish bristles. The name subsp. albidum has been applied to our plants, but we follow Cayouette (2004), as it iseems doubtful that the name appies to our plants, and it has not been typified. 

This species is sometimes subsumed into a broad concept of Eriophorum chamissonis, but Cayouette (2004) treats that as a larger, exclusively western species.

Locations

Keweenaw County
Marquette County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. July 23, 2021. https://www.michiganflora.net/species.aspx?id=2946.