SnowbankSnowbank FungiFungi RevisitedRevisited Cathy Cripps, Ph.D. Dept of Plant Sciences & Plant Pathology, Montana State University, Bozeman, MT 59717 Abstract American phenomenon. They are not associated with the open The snowbank fungi are a taxonomically and ecologically diverse snow-beds of arctic and alpine habitats, nor are they associated group of fleshy fungi that include both Basidiomycota and with glaciers. They are not the typical spring mushroom flora, Ascomycota adapted to the unique microclimate provided by rem- although a few overlap chronologically with this group. They have nant snows in high-elevation conifer forests. This article is a brief not been reported from the eastern USA as an ecological group. review of what is known of the snowbank fungi that occur in west- The snowbank fungi are well-distributed where certain con- ern North America. ditions are met. They proliferate in regions of high elevation with short, cold summers where snowbanks remain until July. Suffi- Key words: fungi, mushrooms, snowbanks, western North cient elevation is necessary for a deep snowpack in mature forests America, cold climates suffused with downed logs and abundant litter and woody debris. Spring and summer nights must be cool enough to retain the snow- Introduction banks, and days warm enough to provide melt water for the fungi One of my first encounters with the “snowbank fungi” was glis- which fruit as the soil warms and dries. The fungi can occur on sading down a snowy slope, when suddenly just before I hit bare steep slopes or level ground, but snowbanks persist longer on ground, hordes of shiny gray mushroom heads appeared unex- northern slopes and in deep shade where fruiting is protracted. pectedly from the snow glistening in the high elevation sunlight. Fruiting can stretch into July and August at higher elevations. The It quite took my breath away. snowbank fungi are associated mostly with the spruce-fir zone Later I learned that deep in the high-elevation forests of west- (mixed conifers), and particularly with Engelmann spruce (Picea ern North America where snowbanks linger long into summer engelmannii Engelm.), subalpine fir (Abies lasiocarpa [Hook.] Nutt.), months, a unique group of macrofungi flourishes on the melt and lodgepole pine (Pinus contorta Laud.), although they also occur waters released by the white remnants of winter. Fruiting bodies in mixed whitebark pine (Pinus albicaulis Engelm.) forests. It is initiate in the subnivean zone and push up through the snow as it this particular set of trees that provides enough shade to protect melts around them forming small caverns. At the snow-soil inter- against a quick snowmelt (unlike larch or other deciduous trees face temperatures hover around freezing. As warm air and sun at high elevations). These trees are also associated with the myc- reduce the snowbanks, an array of mushrooms and cup fungi is orrhizal “snowbankers” such as certain species of Hygrophorus and revealed along margins in the adjacent melt-water zone. As the Cortinarius and they provide woody substrates for the saprobic season progresses they remain as silent sentinels marking the out- species as well. line of defunct snowbanks with their bodies. The snowbank fungi are a consistent feature of high eleva- A Brief History tion western conifer forests in spring and early summer. They are This taxonomically diverse group was first reported as an eco- reported primarily from the Rocky Mountains and Cascade Range, logical assemblage by Wm. Bridge Cooke in a 1944 article (Cooke, but their distribution stretches from southern Canada to north- 1944) on the fungi of Mount Shasta, California. This was followed ern New Mexico at elevations of 1500 to 3800 m. I have ob- by Subalpine fungi and snowbanks (Cooke, 1955) where he related served them en masse in Colorado, Idaho, Montana, Wyoming, the details of the macrofungi consistently fruiting near snowbanks and Canada, and they are well known in the Pacific Northwest, in spring. The names of the fungi he reported are out of date (but the Sierra Nevada range of California, and the Wasatch Moun- recognizable). This set of fungi was subsequently called the “Snow- tains of Utah. Many of the snowbank fungi are endemic to west- bank flora” by Alex Smith in A Field Guide to Western Mushrooms ern North America. Others also occur outside the West but not (1975). He reported particular species near snowbanks in Idaho in this unique ecological niche. Moser (2004) states “we have noth- where he spent summers, but did not treat the group as a whole ing comparable in Europe.” in an article. In 1965 Orson K. Miller, Jr. contributed the brief The “snowbankers” appear to be a unique western North but informative Snowbank Mushrooms in the Three Sisters Wilderness Area (Miller, 1965). Both Smith and Miller described several new E-mail :[email protected] species of “snowbank mushrooms” and linked additional taxa to FUNGI Volume 2:1 Spring 2009 47 Table 1. Snowbank-associated fungi in the western USA and their ecology. BASIDIOMYCOTA Gilled Mushrooms (dark or pink spores) Cortinarius ahsii mycorrhizal with conifers Cortinarius auchmerus mycorrhizal with conifers Cortinarius clandestinus mycorrhizal with conifers Cortinarius croceus mycorrhizal with conifers Cortinarius “flavobasalis” nom. prov. mycorrhizal with conifers Cortinarius “flavoroseus” nom. prov. mycorrhizal with conifers Cortinarius subalpinus nom. prov. mycorrhizal with conifers Cortinarius (Phlegmacium) spp. mycorrhizal with conifers Entoloma sp. terrestrial Nivatogastrium nubigenum on wood Gilled Mushrooms (white spores) Clitocybe albirhiza terrestrial decomposer Clitocybe glacialis terrestrial decomposer Hygrophorus goetzii mycorrhizal with conifers? Hygrophorus marzuolus mycorrhizal with conifers Hygrophorus subalpinus mycorrhizal with conifers Lentinellus montanus wood decomposer Melanoleuca angelesiana unknown Mycena overholtsii wood decomposer Neohygrophorus angelesianus unknown Strobilurus albipilatus conifer cone decomposer Strobilurus occidentalis conifer cone decomposer Non-gilled Pyncnoporellus alboluteus wood decomposer Tyromyces leucospongia wood decomposer Jelly Fungi Guepiniopsis alpina wood decomposer ASCOMYCOTA Caloscypha fulgens seed pathogen on Picea Discina perlata terrestrial decomposer on yellow cedar litter: Gelatinodiscus{ Callitropsis nootkatensis; syn.: Chamaecyparis nootkatensis Gyromitra montana terrestrial decomposer? Sarcosoma latahense terrestrial decomposer? Sarcosoma mexicanum mycorrhizal with spruce? Plectania nannfeldtii decomposer Abies, Picea litter 48 FUNGI Volume 2:1 Spring 2009 subnivean zone and H. goetzii has been ob- served under 7–10 cms of solid ice where snow has melted and refrozen (Miller, 1965). Hygrophorus goetzii has a small viscid pinkish-cream fruiting body (Hesler and Smith, 1963; Miller, 1965; Miller, 1967). Hygrophorus marzuolus (Fr.) Bres. and H. cae- ruleus O.K. Mill. have large, fleshy bluish- gray sporocarps, but only the latter has a strong smell of rancid meal (Miller, 1984; Bessette et al., 1995). Hygrophorus subalpi- nus A. H. Sm. is a robust pure white mush- room with a gelatinous veil at first, and is sold in markets as an edible in the Pacific Northwest. Neohygrophorus angelesianus (A. H. Sm. and Hesler) Singer combines the macro-features of Hygrophorus and Clito- cybe, and produces small brownish-gray Hygrophorus goetzii. Photo by Steve Trudell. mushrooms with drab purple brown tints and decurrent gills; the red reaction of western snowbanks in a number of publi- twigs, cones, and organic debris, except fresh gill and stem tissue to KOH is dis- cations (references at end). Ammirati and for Caloscyphe fulgens which is a seed patho- tinctive (Smith and Hesler, 1942; Miller, Moser joined in to help delineate snow- gen. 1965; Miller, 1967; Bessette et al., 1995). bank Cortinarius taxa, an ongoing process. Several species of Cortinarius are asso- More recent literature has updated the Gilled Snowbank Mushrooms ciated with snowbanks (Miller, 1965) and nomenclature (Bessette et al., 1995; Miller All snowbank species of Hygrophorus are others occur later in the spring grading and Miller, 2006; Redhead et al., 2000). endemic to North America, with the ex- into the typical spring mushroom flora. Moser described the snow-bank fungi ception of H. marzuolus which is reported Cortinarius ahsii McKnight first described as a uniquely North American phenom- from Europe in spring but not necessarily by McKnight is a nondescript brown mush- enon (2004). This insight brings with it the with snowbanks (Moser, 1955). Hygro- room with a bright yellow veil named for realization that the snowbank fungi are phorus species can initiate fruiting in the Alexander H. Smith (his initials: A.H.S.); dependent on a particular habitat limited to forest-covered mountain slopes with special climatic, geographic, and biologi- cal components. These restricted ranges are directly (habitat reduction, forest thin- ning, fire) and indirectly (global climate change) impacted by human activities. The Snowbank Fungi The snowbank fungi are a taxonomically and ecologically diverse group of fleshy fungi that include both Basidiomycota and Ascomycota adapted to the unique micro- climate provided by remnant snows in high-elevation conifer forests (Table 1). Hygrophorus and Cortinarius species are my- corrhizal genera and have a mutually bene- ficial relationship with conifer trees. Other fungi are saprobic and decompose logs, Hygrophorus subalpinus. Photo by Steve Trudell. FUNGI