Stropharia hornemannii, also known as Conifer Roundhead, is a medium-sized to large agaric with a large slimy purple or olive cap whose gills become purplish with age. The stalk is long and adorned with remnants of the white sheath, extending up to a prominent ring. This mushroom tends to grow in clusters and is often found fruiting from well-decayed wood.

Cap convex to broadly conic as young, sticky, and ranges in colour from reddish-brown to violet-brown or brown. As it matures, the cap becomes broadly convex, nearly flat, or broadly bell-shaped, and it usually fades to tan or pale yellowish brown. The cap is bald, occasionally showing slight radial streaks, and often has white veil remnants near the margin. Gills fairly crowded, initially adnate (broadly attached to the stem) but may be slightly detaching with age. Initially pale grey, they later turn purplish grey to purple-black. Stem more or less equal with a persistent white ring, grooved on the upper surface and dusted with purple-black spore dust. Below the ring, it appears shaggy-scaly with whitish girdles, particularly when young. Spore print purple brown.

Microscopic Features: Spores are smooth, ellipsoidal, measuring 11-13 x 6-6.5μm, and do not have a germ pore.

Stropharia hornemannii on the first-nature.com Web site.
Stropharia hornemannii on the MushroomExpert.Com Web site.