This is hexaploid (2n = 60) dioecious species is a close relative of hypnoides and often confused. It occurs in similar shoreline habitats but its range is much smaller, from the Mississippi Rv. watershed to northern Mexico. There are curious concentrations in Texas, La., Okl. and Kans. (K), which suggest association with flyways for migratory water-fowl. In Ky. it is known only from a few localities along banks of the Ohio and Mississppi Rivers. Compared to hypnoides, reptans has 3 (versus 2) distinctly larger anthers. It has more congested inflorescences (the pistillate subglobose), on largely naked peduncles (versus leafy branches); lemmas tend to be longer (usually 2-4 mm versus 1.5-2 mm); and plants are generally more hairy (F, FNA 25). Some authors have transferred reptans to Neeragrostis, either as a monotypic genus or with hypnoides as well; see citations of W and M. Barkworth (online update of FNA 25). However, such segregation is probably not justified by current evidence (P. Peterson, pers. comm.)