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CHROMOSOME RACES IN CLAYTONIA LANCEOLATA (PORTULACACEAE)
Author(s) -
Stewart Dennis,
Wiens Delbert
Publication year - 1971
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1971.tb09943.x
Subject(s) - biology , polyploid , ploidy , chromosome , botany , chromosome number , b chromosome , chromosome pairing , zoology , karyotype , genetics , gene
Chromosome numbers of n = 8, 12, and 16 were determined for 11 populations of Claytonia lanceolata occurring in the southwestern Rocky Mountains of Utah. No evidence of the wide infra‐populational variation of chromosome numbers known in the related eastern species, C. virginica , was observed. The chromosome numbers in C. lanceolata probably evolved from a base number of x = 8. Diploids(n = 8) apparently produced tetraploids (n = 16) of putative autoploid origin. Pairing relationships, including the presence of univalents, bivalents, and trivalents, suggest the chromosome numbers of n = 12 are triploids derived from natural hybridization between diploids and tetraploids. Higher chromosome numbers previously reported in C. lanceolata from Colorado, and presumably based on x = 12, can be explained by subsequent polyploid increases in the triploids. The diploid and tetraploid populations analyzed in this study occupy different ecological habitats. The diploids occur at lower elevations along the foothills, whereas the tetraploids are restricted to higher montane and sub‐alpine elevations. The triploids were discovered at intermediate elevations.