Essentially, all Illinois Opuntia humifusa were recently reclassified as Opuntia cespitosa. Some of them in the sand areas of central and northwestern Illinois may be reclassified again in the near future per @atozbotanicals , but per Majure's reserarch: https://opuntiads.com/records/opuntia-humifusa-clade-chromo-counts.pdf and https://opuntiads.com/records/TYPIFICATIONS-NOMENCLATURAL-CHANGEs-eastern-opuntia-majure.pdf

All Illinois O. humifusa records, with possibly the exception of reintroduced populations, should be changed to O. cespitosa (or O. macrorhiza, but that's not been fully determined yet.) If you've seen me throw a weird ID on your Opuntia observation in Illinois, that would be why. As my knowledge of the complex doesn't go much past Illinois, I don't intend to review records from other states at this time.

Posted on March 6, 2020 05:22 PM by wildlander