Tricholoma imbricatum
Description
Tricholoma imbricatum is one of a large number of reddish-brown trichomes that are notoriously difficult to identify. It usually can be separated from the others by its dull brown, dry cap, which often is broken up into small scales, especially in the center, and often has short grooves along its edge, medium to large firm fruitbodies, lack of a veil, and growth under pines.
It is found in Europe and North America, where it grows on the ground in coniferous forests. Fruit bodies have a brown to reddish-brown cap up to 9 cm (3.5 in) in diameter, and a stipe that is 3.5 to 4.5 cm (1.4 to 1.8 in) long by 1.0 to 1.2 cm (0.39 to 0.47 in) thick. The gills are initially whitish before developing reddish-brown spots.
Common names: Matt Knight.
Mushroom Identification
Ecology
Mycorrhizal with pines (species of Pinus); growing alone, scattered, or gregariously; summer and fall (also overwinter in warm climates); widely reported in North America but much more common from the Rocky Mountains westward.
Cap
3–9 cm; convex, becoming broadly convex or broadly bell-shaped; dry; radially appressed-fibrillose and streaked in appearance; usually becoming finely scaly; often developing radial splits and fissures; medium to dark brown, with a paler marginal area.
Gills
Attached to the stem by a notch; close; short-gills frequent; whitish to very pale yellowish; discoloring and spotting brownish with age.
Stem
3–8 cm long; 1–2.5 cm thick; club-shaped above a pinched base; whitish at the top, but brownish to brown below; usually not becoming hollow; basal mycelium white.
Flesh
Whitish; not changing on exposure, or changing to pale pinkish in places.
Odor and Taste
Odor sweetish, slightly mealy, or not distinctive; taste not distinctive, or slightly bitter and farinaceous.
Spore Print
White.
Microscopic Features
Spores 4–8 x 4–6 µm; broadly ellipsoid or occasionally subglobose; smooth; hyaline in KOH; inamyloid. Basidia 4-sterigmate. Pleurocystidia and cheilocystidia not found. Lamellar trama parallel. Pileipellis a cutis of cylindric elements 5–7.5 µm wide; brown in KOH. Clamp connections not found.
Similar Species
Tricholoma vaccinum is similar, but grows under spruces and features a reddish-brown to orangish brown cap that becomes much more scaly, as well as a hollowing stem. Microscopic features for these species are too close to be used for identification decisions.
Photo sources:
Photo 1 - Author: Jerzy Opioła (CC BY-SA 4.0)
Photo 2 - Author: Richard Sullivan (enchplant) (CC BY-SA 3.0)
Photo 3 - Author: Aleksasfi (CC BY-SA 3.0)
Photo 4 - Author: Igor (Igor_Yevdokimov) (CC BY-SA 3.0)