The Evolutionary Origin of Talinum teretifolium Pursh

Chromosome pairing in triploid and tetraploid hybrids between Talinum teretifolium (2n = 48) and T. mengesii (2n = 24 and 2n = 48) supports the hypothesis that T. teretifolium arose as an amphidiploid species and that T. mengesii was one of its phylogenetic parents. The numbers of meiotic associations in 56 microsporocytes of triploid and tetraploid hybrids between T. teretifolium and T. mengesii make no sense if the base chromosome number in these Talinums is taken to be 12, but do fit an interpretation based on a base chromosome number of 6 where one-half the chromosome complement of T. teretifolium is assumed to be homologous with the entire chromosome complement of T. mengesii. Talinum appalachianum satisfies extrapolated requirements for the other ancestral species, but crossing attempts between it and T. mengesii in an attempt to reconstruct the evolutionary origin of T. teretifolium have thus far been unsuccessful.