The distribution and variation in seed size of artificial Cercidiphyllum japonicum population were studied in the Ecological Research Station of Mao County.Result showed that the distribution of seed size of C.japonicum was normal.The seed size was(0.4 ± 0.1) mg with the variable range being 0.1-1.2 mg.There were significant differences among the seed sizes of different C.japonicum individuals.The variation range was relatively great with the variance coefficient being 31.8%.The sources of seed size varianc...