Irpex lacteus is a very white resupinate polypore with a hairy cap that is seldom more than 1 cm from its hardwood substrate. The fertile surface is made up of teeth that can be up to 5 mm long. The Ochre Spreading Tooth is nearly identical, just not as white.
Irpex can mean "rake" or "wolf's teeth," and lacteus means "milky." So I like to call this Milky Wolf's Teeth. It's also called Milk-white Toothed Polypore.