ANEUPLOIDY IN CLAYTONIA VIRGINICA

Rothwell , Norman V. (Long Island U., Brooklyn, N. Y.) Aneuploidy in Claytonia virginica. Amer. Jour. Bot. 46(5): 353–360. Illus. 1959.—Within the taxon, Claytonia virginica L., an extensive aneuploid series has been found including the following chromosome numbers: 2n = 12, 14, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30, 32, 34, 36, 48, and 72. Studies revealed that a population could be composed of individuals differing in chromosome number. Pollen fertility appears to be high in natural populations and in plants showing meiotic irregularities. Different karyotypes were found within the taxon; plants having the same chromosome number may have different karyotypes. Hybrids have been obtained as the result of crossing plants differing both in number and karyotype. From all the evidence, C. virginica appears to be able to tolerate transitions from one cytological type to another. The hypothesis is proposed that most of the various numbers have been derived from a haploid complement of 8 chromosomes possessing median centromeres. The following factors are suggested to account for the origin of the different numbers: nondisjunction, univalent lagging, misdivision of univalents, polyploidy, and fertile triploids.