Date of this Version
Published in Transactions of the Nebraska Academy of Sciences, Volume 4 (1977) pp. 35-40.
The closely related species Bidens coronata (L.) Britt. and B. polylepis Blake are morphologically similar and may hybridize readily. Sympatric eastward, the species are allopatric in Nebraska-and adjacent states. Karyotype analysis of the two species revealed not only a number of similarities but also some significant differences. Chromosomal analysis of the awn forms of B. polylepis (designated as varieties by some) revealed no significant differences, indicating, along with morphological evidence, that B. polylepis is- a single taxonomic entity, although phenotypically highly plastic.