Andy, sp is an abbreviation for species. So the name Manfreda sp Comonfort means that this is an unidentified species of Manfreda that was collected near the town of Comonfort. I looked on Google maps and there are at least 10 towns called Comonfort in Mexico. (I didn't check in USA or other country.) So without additional details it's impossible for me to guess which one is the actual one. Dennis in Cincinnati