Abstract: Based on the integrative study of ecology and genetics of Allium wallichii in Mountain Jizu, the 8 popu-lations of Allium wallichii( including a population of Allium var. platyphyllum) can be divided into 6 ecotypes: one Allium var. platyphyllum ecotype,one rock diploid ecotype and four tetraploidecotypes (rock tetraploid eco-type, forest tetraploid ecotype, grassland tetraploid with white flower tetraploid ecotype, grassland tetraploid with purplish red flower ecotype) . The selection of ecological factors (light, soil and biological factor) and the three kinds of valid isolation mechanisms between the populations, such as the chromosomal ploidy variation (genetic isolation) between diploid population and tetraploid population, the habitat isolation between grassland tetraploid population and forest tetraploid population and rock tetraploid population and the phenologic isolation between grassland tetraploid with white flower populatoin and grassland tetraploid with purplish red flower population, for-est tetraploid population and rock tetraploid population etc. are the primary factors that caused the ecotypic for-mation of Allium wallichii in Mountain Jizu.

Key words: Jizu Mountain