The Cracked Cap Polypore (Fulvifomes robiniae) is a parasite and decomposer of Black Locust (Robinia pseudoacacia). It is a tough perineal polypore that can be found year-round.

As the name suggests, the cap features cracked fissures. The cap color light brown when young and later transitions to black with age. The old fruiting bodies can get quite large. It's not uncommon to find specimens that are greater than a foot in diameter. The cap is sometimes covered with algae or moss. The cap is connected to its substrate without a stem (sessile).

The underside hymenophore presents a lighter brownish color, displaying a "sparkly" iridescence. It consists of tiny pores that might not be visible without a hand-lens.

Ethnomycology

The Cracked Cap Polypore can act almost as a "fire battery" or a way to store an ember overnight. Once the fruiting body has been ignited, it can keep an ember going for hours or days. From which future fires can be lit.