Montana Field Guide

Rhizomatous. Stems erect, 5–20 cm. Leaves basal and cauline; blades 1–4 mm wide. Inflorescence of 2 to 5 well-separated spikes; the lowest bract shorter than the inflorescence. Spikes ascending; the uppermost male, 1–2 cm long; the lower female, 8–20 mm long, pedunculate, sometimes arising from the base. Perigynia spreading to ascending, green to tan, glabrous, ovoid, 2.5–3.5 mm long with an obscure beak; stigmas 3. Female scales ovate, tan with pale margins and a green midvein, shorter and narrower then the perigynia. Achene 3-sided, partly filling the perigynium (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

The fruit matures in July.

Carex is a large genus in Montana; the following collection of characters separate Crawe's sedge from others in the state. Crawe's sedge has 3-sided achenes and a slender, terminal male spike less than 20 mm long. It has erect, rather than spreading or drooping, female spikes, and the glabrous, yellow-green perigynia do not have distinct beaks. Of the similar species, Carex livida has whitish perigynia and always grows in peat, and both Carex lanuginosa and C. lasiocarpa have hairy perigynia.

Crawe's sedge grows in wet, gravelly or sandy soil along streams or pond margins, often where there is some natural wave or flow disturbance. It occurs in the valleys and montane foothills, especially where the dominant parent material is calcareous. Common associates include Carex oederi, C. lanuginosa, C. aurea, Juncus balticus, and Potentilla fruticosa.

Crawe's sedge often occupies early successional, riparian habitats that may require flooding to prevent development of soil and vegetation.

This species' response to livestock grazing or trampling is unknown. Crawe's sedge may be vulnerable to alterations in natural disturbance regimes or hydrology as well as developments, such as road construction, that tend to occur in valley bottoms.

STATE THREAT SCORE REASON
Reported threats to Montana's populations of Crawe’s Sedge are impacts to a roadside population. Direct damage to plants or the population by construction and maintenance activities, or indirect impacts characteristic of transportation corridors are potential risks (MTNHP Threat Assessment 2021).