Arrhenia auriscalpium in arctic-alpine habitats: world distribution, ecology, new reports from the southern Rocky Mountains, USA

Abstract

During our investigations of alpine agarics in the central and southern Rocky Mountains, Arrhenia auriscalpium (Fr.) Fr. was collected several times on high mountain localities in Colorado at elevations of 3,350-3,670 m. Arrhenia auriscalpium is a well-known arcticalpine basidiomycete (Agaricales) with a circumpolar distribution, which has previously been reported only once from the USA (outside Alaska).

This is the first formal report of A. auriscalpium from Colorado, and is the highest elevation yet recorded for the fungus. This extends the distribution of A. auriscalpium deep into the North American cordillera to a latitude of 39° N, which is a southern-most extension for true northern alpine habitat. This new information is added to the global distribution of A. auriscalpium which is reported here along with notes on its ecology.