A new species, Elymus fertilis Song Wang ex S. W. L. Jacobs & Barkworth (Gramineae, Triticeae), is described from New South Wales and Queensland, Australia, with a New South Wales specimen being designated as its holotype. Elymus fertilis is similar to E. multiflorus (Banks & Solander ex Hooker f.) Á. Löve & Connor, but differs in having longer awns on the lowest lemma of the spikelet and in growing mostly on basic soils of volcanic origin, whereas E. multiflorus is more common on alluvial soils. A key is supplied for the Australian species of Elymus.