Fig. 1

Sample collection sites different varieties of Aster spp. in the Three-River Source Region (TRSR), China. Note: A-J on the map represent the collection sites of Aster flaccidus (QLAF), Aster diplostephioides (QLAD), Aster tongolensis (BMAT), Aster poliothamnus (MQAP), Aster yunnanensis var. labrangensis (MQAY), A. diplostephioides (MQAD), Aster farreri (MQAF), Aster altaicus (MQAA), Aster souliei (DRAS), A. asteroides (DRAA), respectively. See Additional information (Exhibit 1) for specific sampling point information.