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Cytogeography of Claytonia virginica and Its Allies
Walter H. Lewis, Royce L. Oliver and Yutaka Suda
Annals of the Missouri Botanical Garden
Vol. 54, No. 2 (1967), pp. 153-171
Published by: Missouri Botanical Garden Press
Stable URL: http://www.jstor.org/stable/2395001
Page Count: 19
You can always find the topics here!Topics: Plants, Tetraploidy, Diploidy, Ploidies, Botanical gardens, Polyploidy, Evolution, Biological taxonomies, Plant morphology, Leaves
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On the basis of chromosome numbers from more than 1,000 individuals of Claytonia virginica L. (Portulacaceae) throughout its range, a complex evolution of major cytotypes is discussed in relation to distribution and morphology. Chromosomal diversity is thought to have evolved from a base of n = 6 by hyperaneuploidy to n = 7 and 8 with each race giving rise to widespread and dominant primary tetraploids (n = 12, 14, 16). These in turn, and largely by hypoaneuploidy, formed many secondary tetraploid races, the most significant of which are n = 11 and 15. Higher polyploids from 6x to 12x where x = 6, and 6x and 8x where x = 7 are also discussed. Infraspecific phylogeny is compared with data for two allied species, C. caroliniana Michx. and C. lanceolata Pursh, which show striking parallels with C. virginica in chromosomal evolution. By one morphological character, leaf width, the cytotypes separate into two groups, not along diploid vs. polypoid lines, but rather a narrow-leafed var. acutiflora DC. with n = 6, 7, 12±, and 14± and a broad-leafed var. virginica with n = 8 and 16±.
Annals of the Missouri Botanical Garden © 1967 Missouri Botanical Garden Press