Abstract: Micro-morphological characteristics of lemmas of Agropyron mongolicum Keng from 6 natural populations and 2 cultivars were investigated using scanning electron microscopy. The results showed that there were 14 kinds of variations on micro-morphological characteristics of lemma surfaces, indicating an abundant polymorphism. As far as the distribution pattern of the variations was concerned, the variations mainly existed within populations, and the differentiation among populations was not obvious. It was proved that the variation within populations was greater than that among populations.

Key words: Agropyron mongolicum, micro-morphological characteristics of lemmas, variation patterns