While hiking in Saguaro National Monument West we came across this recently fallen saguaro, Carnegiea gigantea. Close inspection revealed a mushroom at the base. I don't know if the mushroom might have weakened the cactus or if it was benign. I have never seen this on a saguaro before. It was much like a bracken fungus I have seen on trees before. The mushroom was very hard. (The photo is turned 90 degrees to the position of the fungus before the cactus fell.)
I'm very intrigued! I've never looked into cacti as substrate/habitat before. Hopefully there are few large non-resupinate polyporoids that live on Saguaro, to narrow the search. Trolling the internet gave me some species ideas: However, following up on eg. Fomes robusta/Phellinus robustus in G&V's N.A. Polypores, cacti are not listed as a substrate. So far the others I've found are resupinate and I've run out of time today to search more. Has anyone in the forum seen something like this? cheers, frog
Perhaps emailing Yoav Bashan (or any of his associates) at the Bashan Foundation down in LaPaz, Baja California, Mexico where they specialize in mycorrhizal studies on all desert ecosystems may help. Here is the website and contact details link. http://www.bashanfoundation.org/