by A. Dean Stock » Fri Apr 27, 2012 4:18 am
Peter,
There has been a lot of discussion among Utah cactus taxonomists concerning the possible presence of Escobaria m. var. marstonii in northern Mojave Co, Arizona. The original type specimen was from Utah and was lost. Benson later named a new type from northern Arizona which later proved to be E. vivipara. Currently, Dr. Pinkava and others in Arizona do not recognized the taxon and it has not been found again in Utah. I doubt that any of the major cactus taxonomists in Arizona (other than possibly Marc Baker) have ever seen the plants you are referring to and it could be quite important in possibly recognizing the taxon to get a look at it. I've searched for it south of St. George towards Wolf Hole and along both the Hurricane Valley and Main Street Valley but have not seen the plant. Probably be easier if they are in flower. Hope you took photos and that I can get a look at them.
Dean
Albert Dean Stock,Ph.D.