Experimental plant materials of native S. spontaneum were collected from the main valleys of the Min River, Qingyi River and Tuo River in Sichuan Province, China, in September 2008 (Figure 1). According to the sampling method of collecting different populations by Jing and Lu (2003), each local population was sampled by collecting leaf tissues from 5 to 15 randomly selected individual plants, in situ, on the basis of the population size at a selected location. Ramets of each sampled plant were dug up and transplanted to an observation nursery for morphological characterization experiments (data not shown). Totally, we collected samples and germplasm of nine populations consisting of 80 individuals. Location and habitat
conditions of the nine populations are given in Table 1.