| In this paper, with the helps of the ordinary ecological site-study techniques, electrophoresis and the multivariate analyses, from both the levels of morphological and allozymic variation, we studied the differentiation patterns of 29 morphological characters and 6 allozymes of 97 individuals from 7 populations of Euonymus chloranthoides Yang, an endangered plant species which is endemic to Mt. Jinyun of Chongqing. We also studied the relationship between such differentiation and its environment factors. The result shows that:The result of ANOVA of morphological differentiation shows the that 8 of the 29 studied characters indicate notable differentiation among individuals and 6 characters even reach the extremely notable level, which means that there does exist morphological differentiation among the individuals to a certain extent.The differentiation of the studied morphological characters shows that the differentiation of vegetative organs is greater than that of reproductive organs and the differentiation of reproductive organs doesn't reach the notable level, which indicates that the morphological differentiation mainly occurred in the vegetative organs and is caused mainly by environment factors.The result of the cluster analysis at the individuals level shows that most of the individuals from different populations cluster together and the individuals from one or two populations doesn't emerge in some phenons, which means that certain degree of morphological and genetic differentiation occurred among populations. This also reflects that there is genetic heterogeneity among individuals or the variation of micro-habitats in a same population.From cluster analysis at the population level we found that there is obvious differentiation between the populations from East hot spring and the populations from other places, this differentiation probably caused by the geographical isolation among those populations.The value grey relatedness degree matrix between morphological characters and environment factors shows that the content of K in the soil is the most important factor to cause the morphological variation of 26 characters of totally 29 studied. Generally speaking, the content of K in soil, pH of the soil, altitude and the content of hygroscopic water are the most critical factors to cause the morphological differentiation of E. chloranthoides Yang. The dominant factors affecting the growth of the endangered plant E. chloranthoides Yang come from the soil.We have tested 6 allozymic systems, they are PER,CYT,SOD,ES,AMY and MDH. There are totally 42 allozymic bands with 15 loci of which 12 are polymorphic and 3 are monomorphic. The percentage of polymorphic loci (P) is 80%. The mean number ofalleles per locus (A) is 1.8, and the effective number per locus (Ae) is 1.13. The mean observed heterozygosity per locus (Ho) is 0.774, which indicates the high level of overall genetic diversity in this species. But we should note that the genetic divergent level is not high with Gst of 0.206, which indicates that the genetic diversity mainly exists within the population while only 20.6% genetic variation is among the populations. The genetic distance among populations is very small with Nm of only 0.964, which indicates that there is obvious gene flows among the populations to some extent.The result of the analysis on the gray relatedness degree between percentage of loci heterozygosity and environment factors shows that the main factors affecting percentage of loci heterozygosity are the content of K in soil, pH of soil and the altitude. It is in accordance with the result from the analysis on the gray relatedness degree between morphological differentiation and environment factors.According to the percentage of per locus heterozygous and the analysis of allozymic bands, we can deduce that the genetic diversity of this species is still rich. But presently, E. chloranthoides Yang is only with isolated small populations, which will prohibit the gene flow among populations and decline the gene...
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