Validate: XHTML ¤ CSS

Tricholomopsis

Field characters

Pileus: convex to plane, often brightly colored, always with fibrils, flesh often colored, not viscid
Annulus: none (usually)
Stipe: fleshy or brittle (Largent and Baroni, 1988)
Stature: Tricholomatoid - Clitocyboid
Ecology: saprophyte, on decaying wood

Micro characters

Basidiospores: smooth, ovoid, inamyloid
Hyphae: inamyloid, with clamp connections
Cystidia: cheilocystidia large and thin walled, very prominent.
Spore Print: white
Lamellae: often yellow or white, variously attached
Lamellar Trama: regular/subregular of swollen, thin walled hyphae
Pileipellis: often brightly colored, filamentous

Notes

Singer, 1986 lists Megacollybia Kotl. & Pouz. as a synonym (note who the authority of the genus is!). However, Barron, 1999, Roody, 2003 and Bessette et al., 1997 all recognize the genus Megacollybia (M. platyphylla, the only species in N. America)

The photos above are of T. decora (sulfurioides??) sensu Bessette et al., 1997, which Singer, 1986 lists as one of the 18 species in the genus.
If you compare the photos of the lamellae of T. decora with those of M. platyphylla I think you will agree there is a great difference between the two. For those interested, see Singer, 1986's discussion on pages 251-252.