Population Size and Geographical Distribution of Clematis Fremontii Var. Riehlii

Population size has very important bearings on evolutionary processes in any organism. As Dobzhansky (1941, p. 169) has pointed out, however, estimates of population size are available for only a few plants or animals. Among plants, the only such estimates are those of Anderson (1936) on Iris, and Emerson (1939) on Oenothera organensis. This paper presents detailed distributional data for Clemnatis Fremontii var. Riehlii, and a preliminary estimate of its population size.