TAXONOMIC SEPARATION OF KENGYILIA (POACEAE, TRITICEAE) IN RELATION TONEAREST 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 di fferent from those in the identification key to these genera by Baum, Yen, and Yang (1991). These characters collectively support the four g roups Agropyron, Kengyilia, Roegneria, and Elymus as previously define d. The four groups are also supported by the linear discriminant funct ion with an overall rate of 83% correct classification. Length of lemm a 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 glu me awns is also a useful supplementary generic diagnostic. Agropyron a nd Elymus have glume awns, whereas the majority of species of Kengyili a 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.