The evolution and maintenance of parthenogenetic species are a puzzling issue in evolutionary biology. Although the genetic mechanisms that act to restore diploidy are well studied, the underlying ...

1. Geographical variation in the song of Zonotrichia capensis, the Rufous-Collared Sparrow, in northwestern Argentina is discussed. Boundaries between song 'dialects' appear to have been stable for at ...

Bulletin of the Torrey Botanical Club, Vol. 112, No. 3 (Jul. - Sep., 1985), pp. 295-311 (17 pages) ...