Abstract: Hierochloe glabra is a typical clonal grass.Its tiller nodes can propagate two generations.The tiller nodes can survive at most for three years,and the rhizomes for two years.There are two age classes in both tiller and rhizome populations,and the first age class constitutes the majority.The potential clonal populations consist of winterness seedlings of tiller and rhizome buds. It is estimated by the numbers of the potential clonal population that the grass would keep its existing positions and roles in the mixed communities of hay making plots,and would enhance itself as a dominant species in the communities of grazing plots.

Key words: Hierochloe glabra, Clonal population, Rhizome, Tiller node, Vegetative propagation, Age structure, metal elements., cadmium stress, Salix variegata, root vigor