It has a scattered distribution, found on lakeshores, streambanks, and other wet places in central Europe (France, Germany, Czech Rep; extinct in Norway and Italy), Asia (Western Siberia, Khabarovsk, eastern China), and northwestern North America (Oregon, Washington, British Columbia).

[12] Coleanthus subtilis typically blossoms from June through September, with very few occurrences in early May or late November.

[21] Generally, it grows in short-lived, patchy dwarf rush colonies that occupy 60–80% of the available space.

[22] It occurs in widely scattered locations, often in the mud of drained ponds, stream and river banks, and old-water margins.

[12] According to earlier research, the seeds can survive in flooded soil for up to 20 years without losing their ability to germinate.

[13] It is spread by rivers at relatively short distances (hydrochory) and by waterfowl and swamp birds (zoochory).

As a result, seed dissemination by wild ducks can account for the significantly disparate distributions in Bohemian Massif, Saint Petersburg, and Siberia.

[25] The plant was classified to the genus Coleanthus by Wenzel Benno Seidl in 1817 (in Roemer & Schultes: Systema vegetabilium).

[27] The species epithet subtilis (Latin for fine, thin, delicate) refers to the thread-thin stems.

[20] Due to its significant distinctions from other grasses (lack of glumes, erectile tissue, two stamens, and elongated style), some authors place them in their own tribe Coleantheae.