A hordeivirus isolated from horsemint (Mentha longifolia Huds.) was designated as the mentha strain of lychnis ringspot virus (LRSV-M) on the basis of serological relationship with the type strain (LRSV-T) and similarities in nucleotide sequence and properties of genomic and replicative RNAs of the two strains. Four ssRNAs in addition to the three genomic RNAs were encapsidated by LRSV-M coat protein. No genomic sequence similarity was detected between LRSV-M and either barley stripe mosaic or poa semilatent viruses under high stringency conditions, confirming that the hordeiviruses are a group of morphologically similar, but genomically distinct viruses.