CHROMOSOME NUMBERS OF NORTH AMERICAN SPECIES OF ANTENNARIA GAERTNER (ASTERACEAE: INULEAE)

• Published in: American Journal of Botany
• Main Authors: Bayer, Randall J., Stebbins, G. Ledyard
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1981
• Subjects: Ice Sheet
• Online Access: http://dx.doi.org/10.1002/j.1537-2197.1981.tb07845.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fj.1537-2197.1981.tb07845.x; https://onlinelibrary.wiley.com/doi/full/10.1002/j.1537-2197.1981.tb07845.x

Chromosome numbers are presented for 99 populations of 13 species of Antennaria , including A. plantaginifolia, A. neglecta, A. virginica, A. solitaria, A. racemosa, A. corymbosa. A. rosea, A. media, A. Parlinii, A. fallax, A. neodioica, A. canadensis , and A. petaloidea . Four species from the eastern United States ( A. plantaginifolia, A. neglecta, A. solitaria , and A. virginica ) were determined as diploid ( n = 14), and these are all sexual. Diploid counts were also obtained for two sexual species ( A . racemosa and A. corymbosa ) from the western United States. Chromosome counts are presented for two heteroploid agamic complexes occurring in the eastern United States; these include what have traditionally been referred to as A. Parlinii, A. fallax, A. neodioica, A. canadensis , and A. petaloidea . Determinations of 2 n = 56, 70, 84, and 112 were obtained for the A. Parlinii and A. fallax groups, where 2 n = 84 had been the only number previously reported. Numbers of 2 n = 84 were confirmed for A. petaloidea and A. canadensis and 2 n = 56 for A. neodioica . The western United States polyploid species ( A. rosea and A. media ) are reported as 2 n = 56. The presence of apomixis is correlated with polyploidy. The distribution of chromosome numbers in eastern United States Antennaria demonstrates that two diploids and many polyploids occur above the glacial margin, and thus there is an increase in the frequency of polyploidy with latitude. Colonization of the glaciated region by Antennaria following the recession of the Wisconsin ice sheet is also discussed. Many of the polyploids occur only in the glaciated region, thus suggesting a recent origin for these cytotypes. There is evidence indicating that the original base number in Antennaria may be x = 7.