CYTOLOGICAL AND MOLECULAR EVIDENCE FOR TRANSFERRING ELYMUS-COREANUS FROM THE GENUS ELYMUS TO LEYMUS AND MOLECULAR EVIDENCE FOR ELYMUS-CALIFORNICUS (POACEAE, TRITICEAE)

Elymus coreanus and Elymus californicus were studied to describe (1) t heir genomic composition and (2) correct taxonomic alignment based on genomic relationships. The hybrids E. coreanus x Psathyrostachys stolo niformis (NsNs), E. coreanus x Leymus ambiguus (NsNsXmXm), E. coreanus x Leymus salinus ssp. salmonis (NsNsXmXm), and E. coreanus x Leymus i nnovatus (NsNsXmXm) averaged 5.80, 13.74, 13.15, and 13.58 bivalents p er cell, respectively. Genome-specific RAPD assay results indicate tha t E. californicus and E. coreanus have the Ns genome but lack the Si g enome from the genus Pseudoroegneria and the E-h genome from the genus Thinopyrum. Therefore, these two species have the same genome constit ution as other Leymus species and should be transferred to the genus L eymus. The following new name combination is proposed for Leymus corea nus (Honda) K. B. Jensen & R. R-C. Wang comb. nov., based an Elymus co reanus Honda (1930 [J. Fac. Sci. Univ. Tokyo 3, 3:17], cited in Love 1 984). However, until further cytological data are available, the new n ame combination transferring E. californicus into Leymus will be made in a later publication.