| Abstract: | Kengyilia Yen et J L Yang is a recently established genus in trib. Tritieeae ofPoaceae. In this paper, this genus is taxonomically revised, and a new taxonomic system ispresented. The new system includes 3 sections, 26 species and 6 varieties, of which 3 sections and 1 species are described as new, 7 taxa are treated respectively in the ways of newstatus or combination and reduction. Three new sections, sect. Kengyilia, sect. Stenachyra L. B. Cai and sect. Hyalolepis (Nevski) L. B. Cai, are differentiated by thelength and width of spike, the growing position of spikelet, the relative length of glume, thecolour of anther and so on. The sect. Kengyilia contains 9 species, distributed in northwestern China, extending westward to Kazakhstan, Kirghizia, Tadzhikistan, Afghanistan and Iran; the sect. Stenachyra L. B. Cai comprises 10 species and 3 verieties, distributed inwestern China, mainly in the Qinghai-Xizang Plateau; and the sect. Hyalolepis (Nevski)L. B. Cai consists of about 7 species and 3 varieties, distributed in western China, extendingwestward to Kirghizia and Tadzhikistan. Twenty-six species of Kengyilia are recognized onthe basis of the same criterion of specific concept, and the other taxa below the rank ofspecies are also checked in terms of their external morphology. As a result, Kengyilia pen~dula L. B. Cai is reported as a new species; K. hirsuta var. obviaristata L. B. Cai israised to a species; K. melanthera (Keng) J. L. Yang, Yen et Baum is reduced to a variety under K. thoroldiana (Oliver) J. L. Yang, Yen et Baum; Roegneria hirsuta var. leiophylla Keng et S. L. Chen is reduced as a synonym of K. hirsuta var. hirsuta; Agropyron thoroldianum var. lasciusculum Melderis is reduced to K. grandiglumis (Keng et S.L. Chen) J. L. Yang, Yen et Baum; Roegneria rigidula var. intermedia Keng et S. L.Chen to K. rigidula (Keng et S. L. Chen) J. L. Yang, Yen et Baum; R. hirsuta var.variabilis Keng et S. L. Chen and R. rnelanthera var. tahopaica Keng et S. L. Chen toK. hirsuta (Keng et S. L. Chen)J. L. Yang, Yen et Baum. In addition, new records onthe geographical distributions of some taxa are also reported in this paper. |
