Objective To reveal the degree and pattern of phenotypic variation in natural populations of P. sheareri.

Method Base on the 20 populations of P. sheareri in its distribution area, a systematic study of 11 phenotypic traits of P. sheareri and their correlation with geo-ecological factors was carried out through nested analysis of variance (ANOVA) .

Results There were extremely significant differences among and within populations in the 11 phenotypic traits of P. sheareri , with coefficients of variation (CoVs) ranging from 8.54% to 43.75%, with a mean value of 20.83%, and the mean CoV of six leaf traits (26.27%) was higher than that of five seed traits (14.31%), which implies that the seeds had greater genetic stability than the leaves. Inter-population variation (50.44%) of P. sheareri was higher than intra-population variation (23.42%), with an average phenotypic differentiation coefficient of 66.46%. Inter-population variation was the main source of phenotypic variation in P. sheareri. Within the surveyed distribution range, the leaves became smaller with increasing altitude, showing a trend of widening from west to east, while the seed size showed a trend of increasing from northeast to southwest. Based on the leaf and seed traits, the 20 populations could be clustered into three major groups, which basically represent the phenotypic characteristics of P. sheareri in different distribution areas.

Conclusion There are significant differences among and within populations among the 11 phenotypic traits of P. sheareri, with inter-population variation being the main factor. The mean CoV of leaves is higher than that of seeds, showing a gradual widening trend from west to east, while seeds gradually increase from northeast to southwest. The 20 natural populations of P. sheareri are divided into three groups according to geographical location through cluster analysis.