Cytological Studies in the Genus Amaryllis

One species and eight horticultural varieties of Amaryllis show a basic number of x=11, which is the predominant basic number of the family. In both Amaryllis belladonna and Amaryllis-Mrs. Garfield the normal somatic number is 2n=22. All the seven colour varieties of Amaryllis-Giant Dutch have 2n=44 chromosomes. These varieties differ from one another in the minor alterations of the chromosome types suggesting the role of minor structural alterations in evolution. In addition to the normal somatic complement a number of variant nuclei with altered karyotypes have been recorded.