Amanita nivalis

Description

Amanita nivalis is a species of basidomycote fungus in the genus Amanita. This small species, often white at first, but with its cap taking on grayish and pale ochraceous tints as it matures. The name was not meant to imply that the pileus is always white, but that the species occurred in areas of deep snows—such as the peaks of the hills of Scotland, from which the original collection came.

This mushroom grows in subarctic and alpine conditions in Europe and also in Greenland. It is often associated with low-growing willows (Salix spp.) and birches (Betula spp.). Recently, the species has also been reported from high elevations in the Rocky Mountains of western North America with dwarf willows. The fruit bodies appear singly or in small groups in both silicaceous and limestone areas in summer. The edibility of this species is not known but because of its rarity, it is best not to gather it.

Common names: Snow Ringless Amanita, Mountain Grisette.

Mushroom Identification

1. Cap

   The cap is 20 - 70 (-80) mm wide. It may be decorated with small bits of the membranous volva. Its marginal striations occupying one-fifth to one-third of the cap radius.

2. Gills

   The white to off-white to cream gills are free or very narrowly connected to the stipe, more or less crowded; and short gills are truncated or rounded truncate, but are usually few and scattered.

3. Stem

   The stem is 38 - 100 × 5 - 12 (-15) mm, white, and usually exannulate—although sometimes it bears an ephemeral ring. The stipe has a flaring, saccate, white to pallid ochraceous volva at its base.

4. Odor and Taste

   The odor and taste of the species are indistinct.

5. Spores

   The spores measure (8.2-) 10.0 - 13.5 (-21) × (7.1-) 8.8 - 12.0 (-19.5) µm and are globose to subglobose (occasionally broadly ellipsoid, rarely ellipsoid or elongate) and inamyloid. Clamps are not observed at the bases of basidia.

6. Spore Print

   White.

History

It was first described by the Scottish mycologist Robert Kaye Greville in 1826 from specimens found growing at high altitudes in the Scottish Highlands. He gave it the Latin epithet nivalis (of the snow) to indicate the alpine-type habitat in which he found it growing rather than to describe its white color.

Photo sources:

Photo 1 - Author: Nicolò Oppicelli (Nicolò Oppicelli) (CC BY-SA 3.0)