Snow false morel

Description

The snow false morel is a spring mushroom with a brain-like, wavily folded head 5–15 cm in diameter, in colours from pale olive-yellow to ochre, darkening with time. The stem is white or pale ochre, thick, short, grooved and hollow inside. The whole fruiting body is brittle and waxy.

It grows from March to May in damp deciduous forests, especially birch and hornbeam, and also spruce forests, on decaying wood and bark buried in the ground.

It looks similar to the very poisonous false morel and is sometimes mistaken for a morel. There is no simple feature for recognising it in the field, so do not collect it for eating. Only microscopic examination of the spores distinguishes them reliably.

Identification features

Cap

The fruiting body is a "head" 5–15 cm in diameter (according to some descriptions up to about 10 cm wide and 6 cm high), irregularly, wavily or brain-like folded, with lobes pressed against the base of the stem or fused with it. Colour from pale olive-yellow to ochre-yellow, darkening with age. Hollow and whitish inside.

Hymenophore (underside of the cap)

No gills or tubes; the spore-bearing layer (hymenium) covers the surface of the folded head, as in other sac fungi. Details of the structure — no data.

Stem

White or pale ochre; thick, relatively short, narrowing towards the base, less often slightly bulbous, wavily grooved, smooth, chambered and hollow inside. Length 1/5–1/4 of the height of the head, often as wide as it; it merges smoothly into the head.

Flesh

White, waxy, very brittle; taste mild, no smell. Do not taste it.

Spore print and spores

Spore print white. Spores ellipsoid, finely warty, thickened at the ends, 18–24 × 8–10 µm. In Gyromitra esculenta they are smooth and without thickenings at the ends.

Habitat and distribution

Ecology. Grows on decaying wood and bark buried in the ground, in damp deciduous forests (especially birch and hornbeam), also spruce forests.

Distribution. Recorded in some European countries; it occurs in Poland. In North America very similar, genetically distinct species, Gyromitra montana and G. korfii, grow. Not legally protected in Poland; on the 2006 Red List it has category V (vulnerable). It is not on the Polish Ministry of Health list of mushrooms approved for sale.

Fruiting. From March to May.

What can it be confused with?

• Gyromitra esculenta (false morel) — More common, smaller, usually darker in colour, but these features are not enough for a reliable distinction. Only microscopic examination separates them reliably: the spores of G. esculenta are smooth and without thickenings at the ends. It contains far more gyromitrin and is very poisonous.
• Morchella esculenta (common morel) — Sometimes confused with the morel; detailed differences — no data.
• Gyromitra montana (North America) — A very close relative; it has larger spores.
• Gyromitra fastigiata — Caution: similar protected species (partial protection in Poland), not included in the Atlas. Head brown, irregularly folded, stem white, thick and furrowed; in spring in broadleaf woods on calcareous soils. Do not pick false morels.
• Gyromitra ambigua — Caution: similar protected species (partial protection in Poland), not included in the Atlas. Similar to the pouched false morel but usually smaller and darker, with a violet tinge on the stem; in autumn in conifer woods. Do not pick false morels.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• English common names include snow false morel, snowbank false morel, calf brain and bull nose.
• The species was described in 1834 by Julius Vincenz von Krombholz as Helvella gigas; it was moved to the genus Gyromitra in 1878 by Mordecai Cubitt Cooke.
• The gyromitrin content is about 1500 times lower than in the false morel, yet eating it is still advised against.
• In North America there are closely related but distinct species, G. montana and G. korfii.