[tikichick]

The closest thing I can think of to lichens would be to use the fake spanish moss from zoo-med or maybe it's fluker's. Close second would be the stuff they sell at the hobby stores for model railroad scenery - there's lots of textures and colors and it's usually loose material that you apply with glue. I have no idea what it's made out of or if it's safe for use with critters, though. Woodland Scenics Field Grass, Flock Grass, Flowers, and Lichens