Hemipholiota sp.
Working species ID is possibly: Destructive Pholiota (Hemipholiota populnea). The cut end of the tree it is growing from was over ten feet above ground
The description below the photo is for fungal nerds.
Possibly: Destructive Pholiota (Hemipholiota populnea) which fruits on the wood of hardwood logs, especially cottonwood. It often grows from cut ends of logs or from naturally damaged areas on logs. It also grows from living trees sometimes.
Hemipholiota is a genus of agaric fungi in the order Agaricales. It was originally proposed by Rolf Singer in 1962 as a subgenus of Pholiota to contain species with absent or sparse pleurocystidia and absent chrysocystidia. Henri Romagnesi raised it to generic status in 1980, but this naming was invalid as it did not meet the requirements of the International Code of Nomenclature for algae, fungi, and plants. Marcel Bon published the genus validly in 1986.
Molecular analyses revealed that Hemipholiota was distinct from Pholiota and also from a new genus Hemistropharia that had been classified with Hemipholiota. Both genera fall outside of the Strophariaceae. The generic name required conservation against an older obscure name.
Thanks for the photo and interesting tutorial. While in my rambles in the woods of upstate New York and New England, I have never encountered this fungus, I am always eager to learn something new about the natural environment.