Hydnochaete olivacea
This spreading toothed fungus is found growing on dead or dying hardwood
tree branches.  Can be found year round; has tiny bristle-like spines on the
individual teeth.  
Order Hymenochaetales.
Description and images at
Fungi Growing on Wood
See Macrofungi Associated with Oaks of
Eastern North America
(2008), D.E.
Binion, et al., p. 349.