Carex pallescens L.
Click to enlarge
Carex pallescens var. neogaea
Basis for Listing
This unusual sedge is primarily an eastern species with rare or infrequent occurrences in the Great Lakes region. Carex pallescens is believed to reach the western limit of its core range near the shore of Lake Superior in northeastern Minnesota. There are also conflicting reports of disjunct occurrences in the Pacific Northwest. Records indicate that C. pallescens has always been rare in Minnesota but that it has probably suffered a significant decline corresponding to habitat loss. It seems to be particularly vulnerable to impacts from rural and suburban development projects, road building and maintenance, and certain high-intensity recreational activities. Carex pallescens is listed as a special concern species in Wisconsin and Tennessee and as a threatened species in Ohio. It has been listed as endangered in Minnesota since 1996.
Carex pallescens is not a particularly cryptic species, but like all members of the Carex genus it will require patience and attention to fine detail to make an accurate identification. It is most similar to the common C. torreyi (Torrey's sedge), which grows in the same area but in slightly different habitats. Both are about knee high, have narrow, hairy leaves and somewhat drooping clusters of perigynia (seeds). However, the perigynia of C. pallescens are measurably narrower than those of C. torreyi (less than 1.5 mm (0.06 in.) wide) and they lack a beak at the apical end.
Minnesota populations occur on the margin of fire-dependent forests of Pinus spp. (pine), Picea spp. (spruce), Populus spp. (aspen), and Betula spp. (birch), adjacent to the Lake Superior shore. Within this forested matrix, C. pallescens seems to prefer low, moist, grassy or rocky habitats at the edge of the forest where it receives partial sunlight. It may also occur in roadside ditches and artificial openings.
Biology / Life History
Carex pallescens is a wind-pollinated perennial. It does produce short rhizomes (underground stems), but they do not allow the plant to spread any great distance. Dispersion appears to rely solely on the production and dissemination of seeds. It produces approximately 50-150 seeds each year, which are shed in midsummer. The mechanism by which these seeds get from one place to another is largely unknown, but may involve water or animal transport.
Conservation / Management
The only place where C. pallescens has been found in Minnesota is near the shore of Lake Superior, a region that has been experiencing unprecedented growth and development in recent years. This growth has resulted in the incremental loss of habitats that are critical to the survival of this species. Only a few sites are currently known to support C. pallescens.
Conservation Efforts in Minnesota
Portions of the Lake Superior shoreline and adjacent native plant communities have been surveyed for rare plants by the Minnesota DNR County Biological Survey. The results of the survey form a sound basis for developing a conservation plan for the few known C. pallescens populations.
Ball, P. W., and A. A. Reznicek. 2002. Carex. Pages 254-572 in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 23. Oxford University Press, New York.
Gleason, H. A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. Second Edition. New York Botanical Garden, Bronx, New York. 910 pp.
Herkert, J., editor. 1991. Endangered and threatened species of Illinois: Status and distribution. Volume 1 - Plants. Illinois Endangered Species Protection Board, Springfield Illinois. 158 pp.
Lakela, O. 1954. Previously unreported plants from Minnesota with additional place records of rarities. Rhodora 56:39-41.
Ownbey, G. B., and T. Morley. 1991. Vascular plants of Minnesota: a checklist and atlas. University of Minnesota Press, Minneapolis, Minnesota. 320 pp.
Wheeler, G. A., and G. B. Ownbey. 1984. Annotated List of Minnesota Carices, with phytogeographical and ecological notes. Rhodora 86:151-231.