Mosyakin has shown that the name P. hirsutissima has been misapplied to eastern pasqueflower when Pulsatilla is maintained as a separate genus, and that the correct name for this species is P. nuttalliana. This encompasses both East Asian and North American material. The species may be further segregated into subsp. multifida (East Asian) and subsp. nuttalliana (North American) but I have not yet attempted to split these. I do follow Mosyakin in distinguishing these taxa from P. patens s.s.