Carex tenuiflora

Carex tenuiflora is a wide-ranging perennial graminoid found in a variety of wetland habitat types, including wet woodlands, lowlands, and mires, especially sphagnum bogs. It has a circumboreal distribution, occurring in northern Eurasia and northern North America, from Alaska, United States, and throughout Canada south to Massachusetts, New York, Ohio (possibly extirpated), Wisconsin, Minnesota, Montana, and Washington, disjunct in Colorado, in the United States. There are over 900 estimated occurrences, which face threats from development, grazing and trampling by livestock, rights-of-way maintenance, logging, hydrological alteration, invasive species, and other threats in some places. Little is known about trends, but with a large range extent and large number of occurrences, abundant habitat, and broad habitat preferences, this species is considered secure.

Carex tenuiflora has a circumboreal distribution, occurring in northern Eurasia and northern North America, from Alaska, United States, and throughout Canada south to Massachusetts, New York, Ohio (possibly extirpated), Wisconsin, Minnesota, Montana, and Washington, disjunct in Colorado, in the United States (FNA 2002). Range extent was estimated to be approximately 60 million square kilometers using herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2025 (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).

By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2025, it is estimated that there are over 900 occurrences rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, RARECAT 2025, SEINet 2025).

Although threats are not widely documented, this species is threatened by development, grazing and trampling by livestock, rights-of-way maintenance, logging, hydrological alteration, invasive species, and other threats in some places, though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this species (NatureServe 2025). However, their overall impact is likely negligible given the species' broad range, large number of occurrences, tolerance of light disturbance, and affinity for typically abundant habitats, as well as no obvious intrinsic vulnerabilities.