Poroid crust on hardwood.

From https://www.mycoquebec.org/bas.php?trie=P&l=l&nom=Perenniporia%20subacida%20/%20Polypore%20acidul%C3%A9&tag=Perenniporia%20subacida&gro=114 on Perenniporia subacida (which is often on conifers): "P. medula-panis and P. tenuis, similar, have more flexing vegetative hyphae, inactive in the Melzer or only slightly dextrinoids, more truncated spores, narrower, and grow on hardwoods." (translated from French)