Hydnoporia olivacea
Can be found year round; has tiny bristle-like spines on the individual
teeth.  
Order Hymenochaetales.  Formerly Hydnochaete olivacea.
Hydnoporia olivacea
Hydnoporia olivacea
See Macrofungi Associated with Oaks of
Eastern North America
(2008), D.E.
Binion, et al., p. 349.
Hydnoporia olivacea