Cytological studies of hybrids between tetraploid (2n = 40) B. intermedia and both C. parviflorum and C. spicigerum indicates a close homology between the chromosomes of the two genera. It is suggested that chromosome pairing may take place autosyndetically. Apparently natural hybridization takes place only at the tetraploid level, and after the species have become apomictic. Each genus seems to represent a valid taxocomic unit on morphological grounds, and no good purpose would be served by uniting them.