Rare Species Guide

  Synonyms

Parmotrema stuppeum, Parmelia claudelii, Parmelia maxima

  Basis for Listing

Parmelia stuppea has an Appalachian-Great Lakes distribution in eastern North America, but it also occurs along the Pacific Coast. It is fairly common in the southern parts of its range, but is rare in the Lake Superior region. This lichen typically grows on deciduous trees in open woods and swamps, or on mossy rocks in California. However, one Minnesota population was found growing on Thuja occidentalis (northern white cedar) in Cook County in 1897 (Fink 1910). Parmelia stuppea was originally assigned state special concern status in 1984 because it had not been recently relocated at the original collection site and additional locations had not been found despite extensive survey work. A second Minnesota population was subsequently discovered at a site south of Taylors Falls in Chisago County in 1988, and P. stuppea was reclassified as a threatened species in 1996.

  Description

Parmelia stuppea is a foliose (leaflike) lichen. The thallus (lichen body) is uniformly gray, with very broad, rounded lobes and cilia on the margins. The lobe edges are erect and ruffled, with soredia (powdery reproductive structures) along the lobe margins, but not on the lobe tips. The lower surface of the thallus is black in the center and brown at the margins (Wetmore 1981; Brodo et al. 2001).

  Habitat

In Minnesota, P. stuppea grows on deciduous or coniferous trees in open woods and swamps. It has been found only in the eastern part of the state.

  Biology / Life History

This lichen reproduces asexually, relying on the dispersal of soredia. Soredia contain both fungal and algal components of the lichen, and when dispersed to a favorable habitat can grow into a new lichen thallus.

  Conservation / Management

Populations of P. stuppea would be negatively affected by certain forms of timber harvest, road-building, or development activities that disrupt the precise environmental conditions required by this species.

Searches for P. stuppea may be conducted year-round when they are not covered by snow or ice.

  Conservation Efforts in Minnesota

In an attempt to identify and possibly preserve local populations, scientists are searching for this and other rare lichens.

  References and Additional Information

Brodo, I. M., S. D. Sharnoff, and S. Sharnoff. 2001. Lichens of North America. Yale University Press, New Haven, Connecticut. 795 pp.

Fink, B. 1910. The lichens of Minnesota. Contributions from the United States National Herbarium 14(1):1-250.

Wetmore, C. M. 1981 (revised 2005). Keys to the Lichens of Minnesota. Department of Plant Biology, University of Minnesota, St. Paul, Minnesota. 92 pp.