WHAT IS MEANT BY TETRAPLOID AND DIPLOID?
Originally daylilies had only one pair of chromosomes (Diploid) but some were then bred with a double set of chromosomes (Tetraploid) to give improved substance. However many of the newer diploids are as good, if not better, than some tetraploids. Fancy edges occur only on tetraploids, but many diploids have a delicacy of colouring and form not found on tetraploids. If you are interested in hybridizing you cannot cross diploids with tetraploids.