Are we talking a regular flat-bed scanner here?

Yes. I stuffed no end of junk into the scanner. The texture on the top of the Deru tree is the Turbine kitchen sponge (green brillo stuff). There's a tree somewhere with bark made of a cookie I put in the scanner. A friend deposited something from the grocery store labeled "monster fruit" on my desk, the skin of which became the chest-scales of the cloud-tyrant. That's our music guy's scraggly beard on the arms of the Gurog Shaman. That was before I figured out that scraggly fur is really easy to draw. There are some cave-plants that are scans of the pistils of a flower, found alongside the parking lot. And somewhere in the swamps are mossy little islands that I textured with a scan of a co-worker's tongue, turned green.