I've never been so puzzled. One day I walked a certain trail, and none of this stuff was around. Next day, same location: hundreds of patches seen in a thirty-minute walk. What on earth is it? This white feathery growth appears on fallen branches and injured parts of alder trees. There are a few more photos this page of my blog. I'm in zone 8 or zone 9a, or something like that. (Gabriola Island, on the sw coast of Canada.) Any ideas?