Image source: Mushroom Expert
Cap: 3-7 cm broad, convex to broadly convex, expanding with age to broadly convex to plane. Gray to gray greenish, to blueish gray, darker towards the disc. Surface smooth to finely scaly near the center.
Gills: Free, not attached. Pallid to cream, soon pinkish to salmon coloured at spore maturity. Stem: 40-100 mm long by 2-6 mm thick. White to grayish green, often with bluish tones. Flesh often bruising bluish where injured, especially near the base. Base of stem bruising bluish.
Microscopic features: Spores pinkish in deposit, smooth, ellipsoid to egg shaped, 7-8.5 by 5-6 u. Pleurocystidia fusiform to lageniform, with or without hooked ends, 58-90 by 10-22 u and with an apex 5-10 u thick. Cheilocystidia pear shaped to clavate to cylindrical or slightly lageniform, 30-85 by 8-20 u.
Habit, habitat, and distribution: Widely distributed across the United States, the British Isles, and Northern Europe. This mushroom is often found in deciduous woodlands in riparian habitats, typically on alder (Alnus), willow (Salix), or on their woody debris. Comments:
Weakly to moderately active. Stijve and Kuyper (1985) reported 0.05-0.25 psilocybin, no psilocin, and from zero to 0.008 baeocystin. Christiansen et al. (1984) found 0.35 psilocybin and 0.011psilocin. See also Saupe (1981) and Stijve and Bonnard (1986). The Field Guide to Mushrooms of Southern Africa by G.C.A. Van der Westhuizen and Albert Eicker (1994) lists Pluteus salicinus
as edible although their description lacks any mention of a bluing reaction. This species may have races that vary in their chemical content from region to region, much in the same way as Gymnopilus spectabilis
. Caution is advised.