We actually found this cactus cutting at the Victorville dump where we took the leftovers from the darkroom installation! It has tentatively been identified as a South American Cereus. When I have the time to complete the identification, I'll go to the best Cactus Guide on the internet.

San Bernardino County has a great Solid Waste Management Department . There are plenty of disposal areas, prices are reasonable, and the staff is very friendly. They let John walk away with the cactus:-)