-- field key --

Tooth Fungi: these have spine-like teeth under the cap but the mushrooms can be either stalked (on the ground) or stalkless (on trees); in the latter case looking either like icicles or a layered polypore; summer and fall.

Sweet tooth
Hydnum repandum
Scaly tooth
Sarcodon imbricatum

Velvet tooth
Hydnellum velutinum
Tooth Fungus

Bear's head
Hericium erinaceus
Northern tooth
Climacodon septentrionale

Tooth fungi look alikes -- but they are polypores:

Violet toothed polypore that looks like a tooth fungus
Trichaptum biforme
Toothed polypore -- it looks like a tooth fungus
Irpex lacteus