Tu (2000) states that the annual M. vimineum can be distinguished from Virginia cutgrass, Leersia virginica, which M. vimineum frequently grows alongside, by M. vimineum’s ciliate leaf sheath collars and paired spikelets; L. virginica has glabrous or pubescent leaf sheaths and 1-flowered spikelets. Corrigan (Undated) states that glumes are present in M. vimineum, while they are absent in L. virginica. Nodes are glabrous in M. vimineum and hairy in L. virginica. In the fall, identification becomes somewhat easier after M. vimineum develops a slight purplish tinge (LaFleur 1996, Swearingen 2000, in Tu, 2000).
Pennsylvania smartweed lacks the silver midrib on the leaf which distinguishes M. vimineum.