Cortinarius boulderensis

While there are at least 21 occurrences reported worldwide (including the European variety named by Moser), there are only 14 confirmed extant occurrences in North America, of which 11 lie in currently protected forest reserves. Cortinarius boulderensis is uncommon to rare in the Pacific Northwest, North America. It is known from several collections in Washington and Oregon, and one occurrence each in California and Idaho. Its patchy distribution precludes estimation of population size and area of occupancy. The current known populations are believed to be stable. Unprotected occurrences will be threatened by road construction and development, and clearcutting or heavy thinning. All occurrences are imperiled by hot fires or other natural catastrophes.

In the Pacific Northwest of North America, Cortinarius boulderensis ranges from the Olympic Peninsula south to Mt Rainier National Park and extends west of the Cascade Range crest south to the area near Castle Crags State Park in California. (Smith 1944, Norvell 1955, Castellano et al. 1999, ISMS 2002 database and map for COBO7). It is not known whether the NAMA foray collection (voucher apparently not retained) occurred in the Priest Lake region of northern Idaho or was brought to the foray by one of the attendees. No information is readily available to this contractor as to the European occurrence (Norvell 2002 pers comm).

There are at least 21 occurrences represented by 27 collections of Cortinarius boulderensis in Washington, and perhaps Oregon and California, Idaho, and Europe . Continued fungal surveys may uncover more sites. (Smith 1944, Norvell 1995, Castellano et al. 1999, ISMS 2002 database; NAMA 1968 Idaho foray list, Moser 1981). The Idaho occurrence is based on a foray list. The European occurrence is based on a variety named by world Cortinarius expert Meinhard Moser: C. boulderensis var. pallidulus.

Whatever threatens the extant forest will threaten the fungus. This species has been collected primarily from late-successional old-growth forests. Populations are inferred to be long-lived: e.g. it is possible that collections made in the Olympic Hot Springs type locality from 1941 to 1993 represent one population (Smith 1944, Norvell 1995). Like the forest, Cortinarius boulderensis is threatened by hot fires, road construction or other development, and clearcutting (Norvell pers comm 2002).