This largely tropical or subtropical species is now widely scattered as an adventive species across southeastern states (K). It has been considered native to both Western and Eastern Hemispheres, but J.K. Wipff (FNA 25) indicated only the Eastern. Both ischaemum and violascens have spikelets in groups of 3(-5) at least along middle portions of inflorescence branches; fertile lemmas are light to dark brown or blackish; leaves are largely glabrous; 2n = 36 (FNA 25). D. violascens differs from ischaemum in its lack of axillary panicles, smaller spikelets (1.2-1.7 mm long versus 1.7-2.3 mm), unequal glumes (x 0.75 versus subequal), and lack of capitate hairs in spikelets (FNA 25, W).