Variation

Geographic Variation in Red-backed Mice (Genus Clethrionomys) of the Southern Rocky Mountain Region

E. Lendell Cockrum
Kenneth Leonard Fitch

Geographic Variation in the Harvest Mouse, Reithrodontomys megalotis, On the Central Great Plains And in Adjacent Regions

J. Knox Jones
B. Mursaloglu

Morphological Variation in a Population of the Snake, Tantilla gracilis Baird and Girard

Charles J. Cole
Laurence M. Hardy

The Effects of Cross & Self-Fertilisation in the Vegetable Kingdom

Charles Darwin

Species and Varieties, Their Origin by Mutation

Hugo de Vries

The Different Forms of Flowers on Plants of the Same Species

Charles Darwin