Abstract
1. Random genetic drift which is a factor in evolution was studied by means of considering the chromosomal variation in natural populations of Trillium kamtschaticum.
2. Homogeneity of chromosome constitution was expressed by the “Number of types per chromosome”. abbreviated as N.T.C., and the rate of decrease of N.T.C. in relation to population size was calculated.
3. Actual values of N.T.C. in various populations of T. kamtschaticum were calculated. It seems adequate to conclude, with reference to ecological, geological and historical background, that the values of N.T.C. indicate the effectiveness of random genetic drift in determining the genetic constitution of natural populations.
