This widespread variable species occurs in wetlands across temperate and boreal regions of North America, but it is most common in cool temperate zones. It is diploid (2n = 20). Unusually robust plants (with leaves up to 9 mm wide and culms to 4 mm) may resemble the more northern diploid, G. grandis S. Walson, or the more western diploid, G. elata (Nash) M.E. Jones. However, those species are unknown in Ky. or nearby, except perhaps for grandis in se. Ohio (K). Other species in Ky. are tetraploids, but occasional triploid hybrids with striata are possible (FNA 24).