Mushroom of the Month was...
Meripilus giganteus: the Black-Staining Polypore
The black-staining polypore can be a very large mushroom. It can be as large as three feet across. It can be confused with the hen-of-the woods mushroom, Grifola frondosa and with Bondarzewia berkeleyi. The three species all have multiple fleshy, flattened caps on a single central stalk. Meripilus giganteus is the only one whose pores stain black with handling or age. Both B. berkeleyi and M. giganteus can be larger than G. frondosa and both can have larger caps.
Meripillus giganteus will start as a lumpy, misshapen roseate mass. It will grow into a large, rosette-like shape consisting of multiple fan shaped caps attached to a central stalk. Fully grown the mushroom can range from 20 to 36 inches across and about a foot high. The fan-shaped caps range from 2 to 10 inches across and are fairly thick, ½ to ¾ inches. The caps start out grayish to yellowish tan and gradually dark with concentric zones of darker and lighter brown darkening to black at their edges/margins. The flesh is white, the pores are white but blacken when bruised. The stem is very short and thick. The spore print is white as is the spore print of G. frondosa. B. berkeleyi has an pale to orangish yellow spore print.
The black-staining polypore is edible so a mistaken identity as G. frondosa does not have dire consequences. I have not tried this mushroom though Lincoff gives it a good rating in the Audubon Guide. Phillips merely lists it as edible.