DONALD PINKAVA’S JOURNEY FROM ASTERACEAE TO CACTACEAE: FROM THE OHIO STATE UNIVERSITY TO ARIZONA STATE UNIVERSITY

Donald J. Pinkava is best known for his application of cytogenetics in unraveling the complex interspecific hybridization in the prickly pear genus Opuntia Mill. in the southwestern United States extending down into northern and central Mexico. Using cytogenetics, Pinkava delimited species boundaries within Opuntia for taxonomic treatments. His work on Opuntia in the Chihuahuan Desert led to later comprehensive contributions in the Flora of North America and the Flora of Arizona that include opuntias not only in the Southwest but in every US state. Pinkava’s systematic knowledge, as reflected in his taxonomic treatments provided the basic scientific framework needed for ongoing conservation of Cactaceae in the Southwest to the present day. Interestingly, the starting point for all of Pinkava’s contributions in Cactaceae began with his initial studies of Asteraceae as a student of T. Richard Fisher at The Ohio State University (OSU), an institution with longstanding research interests in the Asteraceae. It is there that he selected a genus, Berlandiera DC as his dissertation topic. Ironically, this genus has a range from the drier sites of the Eastern Coastal Plains, into the Ozark and Ouachita Mountains, with a disjunct distribution in the mountain floras of southeastern Arizona and Northern Mexico. Like Berlandiera, Pinkava’s own work reflects techniques and training in the eastern US, that migrated and was used as the basis for his groundbreaking studies of Cactaceae in the Southwest.