Fruiting body starting off as a small knob, then shelflike or bracketlike to hoofshaped;
hard and woody, perennial;Cap up to 20 cm or more in width, 2-12 cm thick (or occasionally more). Surface brown and velvety or finely hairy in young specimens or on the surface of the younger and growing lower layer, turning grayish white, then darker brown to almost black all the way up to the older layers, occasionally with alternating lighter and darker perimetrical bands. Usually crusty and furrowed and often cracked in old specimens.
Lower (porous) side grayish brown to brown
Pores tiny, 4-5 per mm.
Flesh gray brown to rusty brown, hard and woody. Taste sour or bitter
Tube layers 2-5 mm long, not always clearly stratified
As above - under the microscope (x56)
Note older (darker and with some white mycelial thread mass)
tube layer on left and younger, lighter one on right.Stalk absent or rudimentary
Spore print: whitish; Spores 5-7 x 4-6 microns, round or roundish, smooth.