What You Should Know
Inocybe lacera is a poisonous species of mushroom in the genus Inocybe. Its appearance is that of a typical "little brown mushroom": small, brown, and indistinct. However, it is distinguishable by its microscopic features, particularly its long, smooth spores. Found in Europe and North America.
This mushroom is found throughout autumn on sandy soil, especially with pine, though it is typically found in mixed woods. It grows mycorrhizally with both conifers and hardwoods, and the fruiting bodies can be found alone, in scattered groups, or growing gregariously. It is most commonly found on the edge of pathways through woodland, and another common habitat is on old, moss-covered fire sites. Other habitats include heathland and coastal dunes.
Other names: Torn Fibrecap.
Inocybe lacera Mushroom Identification
Mycorrhizal with conifers or hardwoods; growing alone, scattered, or gregariously; summer and fall (also spring, at high elevations in Montana, where it grows under Quaking Aspen); widely distributed in North America.
1.5-4 cm; convex to conical, becoming broadly convex or broadly bell-shaped; dry; densely hairy or scaly, becoming cracked and lacerated; brown; sometimes with pale remnants of the cortina along the margin.
Attached to the stem; close or crowded; pale at first, becoming brownish with maturity (and then usually with whitish edges); at first sparsely covered by an ephemeral cortina.
1-4 cm long; up to .5 or nearly 1 cm thick; more or less equal; dry; finely hairy or nearly smooth; pale brownish; rarely with a thin ring zone resulting from the cortina.
Whitish or tan.
KOH on cap gray.
Spores 12-17 x 4.5-6 µ; long-elliptical or cylindrical; smooth. Pleurocystidia 50-70 x 10-20 µ; fusiform or fusoid-ventricose; walls 1-3 µ thick; often apically encrusted. Cheilocystidia similar to pleurocystidia.
Inocybe hystrix is similar in appearance but noticeably more scaly. It is also far less common.
Inocybe lacera Taxonomy
Inocybe lacera was first described by Swedish mycologist Elias Magnus Fries, but was placed into the genus Inocybe by Paul Kummer in his 1871 work, Der Führer in die Pilzkunde. As several forms of the species are recognized, the main variety is sometimes known as Inocybe lacera var. lacera. It is commonly known as the Torn Fibrecap, while in German it is known as Gemeiner Wirrkopf and in French as Inocybe déchiré.
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