Synopsis of the Polyporaceae of the Western United States and Canada

Abstract

This paper presents preliminary taxonomic information which has been developed as part of a general research program directed toward a treatment of the Polyporaceae of North America. A synopsis of the polypores of the southeastern United States (Lowe and Gilbertson, 1961) has previously been published. The area covered here includes the western states of Alaska, Washington, Oregon, Idaho, Montana, Wyoming, California, Nevada, Utah, Colorado, Arizona, and New Mexico; the Canadian provinces of British Columbia, Alberta, and Saskatchewan; and Yukon Territory and the western portion of the Northwest Territories. Much of this area has not been explored mycologically and the wood-rotting fungus flora of most of the area is inadequately known. Increased collecting by regional workers is very desirable, and it is hoped that this paper may stimulate such activity. The richness of a wood-rotting fungus flora seems to depend upon the variety of available substrata and the climatic factors, primarily temperature and amount and distribution of precipitation. Because the western forests are composed largely of gymnosperms, the variety of substrata is much more limited than in eastern North America where, in addition to conifers, a large number of woody angiosperms are found. Also, average annual precipitation in much of western North America is less than 20 inches. In higher elevations in the interior mountains it may be as much as 40 inches, but much of this is snow. Even in the coastal forests, where annual precipitation may total over 100 inches, the summer months preceding the critical fall fruiting period for fleshy fungi are frequently so dry that logging operations are suspended because of the extreme fire danger. The wood-rotting fungi, in contrast to the fleshy terrestrial forms, require a relatively long period of favorable moisture and temperature conditions before their basidiocarps appear in large numbers. From our experience, we judge that in most regions of the West, a favorable season for fruiting of wood-rotting fungi may occur in one year out of five. 474