My brother recently posted about a polypore that had grown around an alder stick, speculating on how this may have happened, given alder’s normally rapid decay, and a polypore’s presumably slow growth.
The post reminded me of a picture I took of a polypore growing on a Mt. Ash (Sorbus aucuparia) about a year ago, where it had grown around a leaf of the tree. Unfortunately, I did not take a picture clearly showing that, but in the photo above, you can see where parts of the leaf stick out from the under surface of the left side of the polypore. This suggests to me that polypores probably are capable of faster growth than one might otherwise suspect from the fairly drab woody polypores (locally often referred to as “bear’s bread”, though that includes several different species, none of which are eaten by bears), especially when it is so easy to see growth layers in some species that imply relatively small amounts of growth from year to year. A quick google search didn’t turn up anything I could find about growth rates of the fruiting bodies of similar polypores.