Snow False Morel

Gyromitra montana belongs to the genus Gyromitra, the false morels, in the family Discinaceae of the order Pezizales. Despite their morel-like silhouette these fungi are not true morels: their fertile surface is a folded, convoluted skin without the sharply outlined pit-and-ridge honeycomb of Morchella, and their stalks are typically short, massive and internally divided into chambers.

The snow false morel is the bulkiest member of the group in western North America. Its head is a cluster of rounded, blunt, brain-like or walnut-like lobes, tan to yellow-brown or ochre, sitting almost directly on a short white stalk so that the whole fungus can look like a knot of dough pushed up through the duff. Large specimens are surprisingly heavy for their size.

It is also one of the most reliably snow-associated fungi of the mountain spring, pushing up at the very edge of retreating snowbanks. The closely related European fungus long called Gyromitra gigas is very similar, and the two names have been used more or less interchangeably in older literature.

Cap

The fertile head is 4-15 cm across and irregularly rounded, lobed or saddle-shaped, composed of broad, blunt, rounded folds and convolutions that look like a brain, a walnut kernel or a wrinkled fist. It is not sharply pitted. Colour is pale tan, yellow-brown, ochre-brown or warm reddish-brown, becoming darker with age. The margin of the head is frequently fused to the upper stalk in several places, so the underside is partly enclosed rather than freely overhanging.

Stipe

The stalk is short and thick relative to the head, often only 2-6 cm tall but 3-6 cm wide, white to cream, and irregularly furrowed and lumpy on the outside. Cut lengthwise it is not simply hollow: the interior is divided by folds of tissue into several irregular chambers and channels, a structure very different from the single clean cavity of a morel.

Flesh & spore deposit

The flesh is white, firm, slightly brittle and relatively thick, without appreciable colour change on cutting. A spore deposit is white to pale yellowish; the spores are elliptical with small apical projections, a Gyromitra trait visible under the microscope.

This species fruits in montane and subalpine conifer forest, typically at moderate to high elevation, on soil, needle duff and rotting woody debris. It is often found within a metre or two of a melting snowbank, in the damp strip where the ground has just been exposed, and it also occurs around conifer logs and stumps, along stream banks and on disturbed forest roadsides. Frequent stand types include spruce, true fir, Douglas fir and lodgepole pine, and it also occurs under aspen in some ranges.

Fruiting tracks snowmelt, so the season runs from early spring at low elevations to early summer high in the mountains, and a single range can produce fruiting bodies over two months as the melt line climbs. Fruiting bodies sometimes emerge partly buried in duff, with only the top of the wrinkled head showing. The range covers the mountains of western North America, with closely comparable fungi across northern Europe and Asia.

Gyromitra montana is generally considered saprotrophic, decomposing buried conifer wood, needle duff and coarse organic matter in cold montane soils, and it is often found near well-rotted logs and stumps. Some observations suggest it may also form loose associations with conifer roots, and the genus as a whole occupies an uncertain position between decomposition and root association.

Growing at the snow line is a specialisation in its own right. Meltwater keeps the soil saturated at a time of year when temperatures are still low and competing fungi are largely inactive, and the fungus can develop under the snowpack and expand rapidly once exposed. Spores are released from the asci covering the outer folded surface of the head and dispersed by wind through the open montane understorey. Ecologically it is an important early-season decomposer in forests where the biologically active period is short.

Gyromitra esculenta has a much more finely and sharply convoluted, distinctly brain-like head that is usually reddish-brown to dark chestnut, a slimmer stalk, and a lighter overall build. Gyromitra korfii and Gyromitra brunnea are eastern North American species with more clearly lobed, saddle-like or gable-like heads and comparatively less lumpy folding. Gyromitra californica has a distinctly saddle-shaped, olive to yellow-brown head with a strongly ribbed stalk that is much more clearly differentiated from the head.

True morels in Morchella are separated at a glance by their regular pit-and-ridge honeycomb surface, their tall proportions and their single continuous hollow interior, in contrast to the chambered stalk and folded, unpitted head of the snow false morel.