What You Should Know
Tricholoma arvernense is a mushroom of the agaric genus Tricholoma. It is characterized by its yellow to orangish cap color, small spores, abundant clamp connections, and association with pines or, rarely, fir.
First described as a variety of Tricholoma sejunctum by French mycologist Marcel Bon in 1975, he promoted it to species status a year later.
Tricholoma arvernense Mushroom Identification
Mycorrhizal with conifers—in Europe, primarily with pines, but in North America apparently with other conifers (possibly spruce, fir, and/or hemlock); growing alone, scattered, or gregariously; late summer and fall; Pacific Northwest.
5–8 cm across; at first convex with a central bump, becoming broadly convex to broadly bell-shaped; dry; finely, radially appressed-fibrillose with brownish-yellow fibrils on a yellowish ground or, near the margin, a whitish ground; the center usually darker and more brown.
Attached to the stem by a notch; close; short-gills frequent; whitish, sometimes staining or discoloring yellow, especially toward the cap margin.
4–8 cm long; 1–2 cm thick; equal, or slightly swollen in the middle; bald; dry; whitish, developing brownish stains in places; basal mycelium white.
White; unchanging when sliced.
Odor and Taste
Spores 4–6 x 3.5–4.5 µm; ellipsoid, with a small apiculus; smooth; hyaline in KOH; inamyloid. Lamellar trama parallel. Basidia 4-sterigmate; 25–38 x 5–7 µm; clavate. Cheilocystidia 20–50 x 10–20 µm; clavate to sphaeropedunculate or irregular; smooth; hyaline in KOH. Pileipellis a cutis; elements 5–7.5 µm wide, smooth, hyaline in KOH. Clamp connections not found.
Tricholoma arvernense Synonyms
Tricholoma sejunctum var. arvernense Bon (1975)
Tricholoma sejunctoides P.D.Orton (1987)
Photo 1 - Author: Adrien BENOIT à la GUILLAUME (Creative Commons Attribution-Share Alike 4.0 International)
Photo 2 - Author: Irene Andersson (irenea) (Creative Commons Attribution-Share Alike 3.0 Unported)