There have been significant advances recently in understanding the processes that operate in mixed-ploidy populations to maintain the coexistence of multiple cytotypes. Trávníček et al.  examine frequent ploidy coexistence in populations of Pilosella echioides in Central Europe and, contrary to theoretical expectations, find no breeding barriers between different ploidies, and that the sympatric growth of [...]

Coexistence of multiple cytotypes of an orchid Large-scale cytotype surveys have indicated that intraspecific ploidy diversification is much more common than previously thought. Trávníček et al. examine inter- and intrapopulational ploidy diversity in the fragrant orchid, Gymnadenia conopsea agg., in Central Europe and find that this species represents a remarkable example of ploidy coexistence in [...]

Genetic relationships between sympatric and allopatric Casearia Casearia sylvestris var. sylvestris inhabits humid, dense forests, while var. lingua is restricted to xeric habitats, yet despite differences in morphology and habitat preference, intermediate forms exist in transitional environments, complicating the delimitation of the taxa. Cavallari et al. examine nine microsatellite markers and conclude that the two [...]