Kuehneromyces mutabilis

Kuehneromyces mutabilis (synonym: Pholiota mutabilis), commonly known as the sheathed woodtuft, is a species of fungus belonging to the family Strophariaceae. It is a widely distributed saprotrophic organism, thriving on dead wood, particularly of broadleaf trees. This mushroom is notable for its edible qualities, although it bears a close resemblance to some poisonous species, making accurate identification crucial for foraging purposes.

Description

Kuehneromyces mutabilis features a convex to broadly convex cap that becomes more flattened with age, measuring 3 to 8 cm in diameter. The cap's surface is smooth and hygrophanous, displaying a characteristic change in color from a rich, tawny brown when moist to a much lighter, caramel or almost yellowish hue as it dries. The margin of the cap is initially curved inward before straightening out in mature specimens.

The gills are adnate or slightly sinuate, crowded, and initially light brown, becoming darker with maturity due to the production of spores. The stem of the mushroom is 4 to 10 cm long and 0.5 to 1 cm thick, cylindrical, and bears a distinctive ring that remains as a sheath at the upper part of the stem. The stem's color matches the cap when moist but becomes lighter as it dries.

Spore print of Kuehneromyces mutabilis is brown. Its spores are smooth, ellipsoid, and measure 6 to 7.5 by 4 to 4.5 micrometers.

Habitat and Distribution

Kuehneromyces mutabilis is found in temperate regions across the Northern Hemisphere. It grows saprotrophically on dead wood, particularly favoring the stumps and fallen branches of broadleaf trees. This fungus is commonly encountered in woodland areas, parks, and forests during spring and autumn.

Edibility

The sheathed woodtuft is considered an edible mushroom, with a pleasant taste and texture. However, it is crucial to distinguish it from its poisonous lookalikes, such as the deadly Galerina marginata. Proper identification involves noting the habitat, as Kuehneromyces mutabilis grows on wood, and observing the distinctive ring on the stem, which is not present in Galerina marginata.

Similar Species

Kuehneromyces mutabilis can be confused with several other species, including the aforementioned Galerina marginata and Pholiota squarrosoides. The presence of a ring on the stem and growth on wood are key identifying features that help distinguish it from these potentially dangerous lookalikes.

Conservation

As a saprotrophic organism, Kuehneromyces mutabilis plays a vital role in its ecosystem by decomposing dead wood and contributing to nutrient cycling. There are no known significant threats to this species, and it is not listed on any conservation red lists. However, habitat destruction and pollution can impact its populations indirectly.