(n)an edible fungus with a broadly convex blackish brown cap and a pore surface that is yellow when young and darkens with age; stalk is thick and enlarges toward the base
The Collaborative International Dictionary of English (GCIDE) v.0.53Collaborative International Dictionary (GCIDE)
a. [ L. pulverulentus, fr. pulvis, pulveris, dust, powder: cf. F. pulvérulent. ] Consisting of, or reducible to, fine powder; covered with dust or powder; powdery; dusty. [ 1913 Webster ]