Pseudochaete tabacina
Pseudochaete tabacina
Pseudochaete tabacina
Pseudochaete tabacina
Pseudochaete tabacina
Pseudochaete tabacina
This fungus spreads and forms caps (effused-reflexed) on old logs and stumps,
growing and producing spores for several years.  Caps develop concentric
zones of color and become very hard, breaking like a thin seashell.  The fertile
(spore producing) surface is orange-brown and covered with tiny, bristle-like
spines.

Order Hymenochaetales. Hymenochaete badioferruginea and Hymenochaete
tabacina
are synonyms (former names).  
See The Audubon Society Field Guide to
North American Mushrooms
, 1981,
Lincoff, p. 439.