Tricholoma arvernense

Description

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.

Mushroom Identification

1. Ecology

   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.

2. Cap

   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.

3. Gills

   Attached to the stem by a notch; close; short-gills frequent; whitish, sometimes staining or discoloring yellow, especially toward the cap margin.

4. Stem

   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.

5. Flesh

   White; unchanging when sliced.

6. Odor and Taste

   Mealy.

7. Spore Print

   White.

8. Microscopic Features

   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.

Synonyms

1. Tricholoma sejunctum var. arvernense Bon (1975)

2. Tricholoma sejunctoides P.D.Orton (1987)

Photo sources:

Photo 1 - Author: Adrien BENOIT à la GUILLAUME (CC BY-SA 4.0)

Photo 2 - Author: Irene Andersson (irenea) (CC BY-SA 3.0)