TAXONOMIC SEPARATION OF KENGYILIA (POACEAE, TRITICEAE) IN RELATION TO NEAREST RELATED ROEGNERIA, ELYMUS, AND AGROPYRON, BASED ON SOME MORPHOLOGICAL CHARACTERS

Based on 100 species representative of the four genera, we scored 290 herbarium specimens for a number of morphological characters. The data were subjected to canonical discriminant analysis using characters different from those in the identification key to these genera by Baum, Yen, and Yang (1991). These characters collectively support the four groups Agropyron, Kengyilia, Roegneria, and Elymus as previously defined. The four groups are also supported by the linear discriminant function with an overall rate of 83% correct classification. Length of lemma awn was found to be an additional diagnostic character as Agropyron and Kengyilia have lemma awns shorter than 5 mm, whereas Roegneria and Elymus have longer lemma awns with very few exceptions. Length of glume awns is also a useful supplementary generic diagnostic. Agropyron and Elymus have glume awns, whereas the majority of species of Kengyilia and more than half of the species of Roegneria lack them. If a glume awn is present it is usually not longer than 1 mm.