This is a large group of mushrooms with white gills that run down the stem, no ring around the stem, and mostly white spore prints. The gills attach to the stem.
The gills aren't waxy, as in the waxy caps, nor brittle, as in Lactarius and Russula. The gills aren't shallow and blunt, as in the chanterelles, and the mushrooms aren't orange, as the Jack O'Lantern and its relatives.
Most are without flavor, such as the giant clitocybe. Some are unpleasant-tasting, and a few are poisonous, but a few, such as the blewit and iris-scented clitocybe, are especially delicious.