Hybridity and the species concept are very complicated issues and come in all shades of grey, but the scenario Donald Barnett describes where an apparently stable hybrid is found in an area with only one parent present is by no means unique. Rodger Whitlock's suggestion: I suggest you simply refer to these plants as "Opuntia × charlestonensis Clokey", with a foot- or side note stating "believed to be a natural hybrid between O. phaecantha and O. erinaceae". is a good one, but I think you could also use the form: " On X mountain is a population of plants that have been described as Opuntia charlestonensis Clokey, which appear to be of hybrid origin with O. phaeacantha and O. erinacea [NB spellings!] as parents, although only O. erinacea is now present. Their status requires further investigation.' This places the plants in their biological context as a population (which is what matters!), relates that population to a taxonomic concept (i.e. Clokey's name) which is a matter of opinion, and leaves the door open for both dissent and agreement. Clokey has already established specific status for these plants, so nothing further needs to be done if that is taxonomic viewpoint taken, but an objective account would also present the alternative view that it could be treated as a hybrid O. x charlestonensis Clokey (no change in authorship needed) on account of the following evidence (...) John Grimshaw Visit John Grimshaw's Garden Diary http://johngrimshawsgardendiary.blogspot.com/ Dr. John M. Grimshaw Sycamore Cottage Colesbourne Cheltenham Gloucestershire GL53 9NP Tel. 01242 870567