My theory is that the mushrooms are growing on the side of a tree 'cause they are trying to put some distance between themselves and the
hoards of mosquitoes that lurk in the swamp below the tree.
Strobist info: A vintage Sunpak 322 hot-shoe flash and a Quantaray PZ-1 DSZ were bounced from a 42" white umbrella positioned at camera right, more or less level with the subject. Both flashes were at full power. The Sunpak 322 was wired direct, and the Quantaray was in slave mode, fired optically. See the setup
here.