Scientific Name
Carex douglasii Boott
Common Name(s)
Douglas' sedge
Tribe / Family Name
Cyperaceae
Flowering Period
May to June
Symbol
CADO2
Description
Douglas’ sedge is a native cool-season perennial rhizomatous grass-like plant. Culms usually range from 10–30 cm in height and has an erect growth habit with obtusely triangular (3-angled) stems that usually exceed the leaves (edges smooth towards tip). Inflorescences contain several spikes that are densely clustered into ovoid heads, up to 3.5 cm long, unisexual (bearing exclusively male [staminate] or female [pistillate] flowers, or nearly so), and typically light brown in color. Bracts are shorter than the inflorescences and scarious-setaceous. Perigynia are usually 3.5–4.5 mm long, up to 2.1 mm wide, ovate to obovate, plano-convex, sharp-margined and finely serrulate distally, glabrous, green to tan, and obscurely many-striated on both surfaces with well-developed marginal nerves; beaks are 1–2 mm long, slender, obliquely cleft, and occasionally bidentate. Pistillate scales are lanceolate to ovate-lanceolate, exceeding or hiding the perigynia, pale brown to whitish hyaline, and awned or unawned. Stigmas 2. Fruits are achenes, lenticular, and glossy brown. Leaves are usually up to 3 mm wide, 3–8 per culm, clumped near the base, firm, and flat or involute. Sheaths are dirty brown or blackish, hyaline ventrally, glabrous, and truncate at mouth.
General Info
Douglas’ sedge can be found along roadsides and forest margins, in dry to wet soils, often alkaline places, sagebrush steppe, riparian zones, campsites, foothills, plains, and montane sites.
Similar Species
Douglas’ sedge is very distinctive and not easily confused with other grass-like species. However, it may appear similar to clustered field sedge (Carex praegracilis). To distinguish Douglas’ sedge from clustered field sedge, examine their inflorescences. Douglas’ sedge has broad, shaggy, inflorescences with tangled stigmas, and clustered field sedge has narrower inflorescences. Also, Douglas’ sedge has brown plant bases and slender brown rhizomes, while clustered field sedge has blackish plant bases and thicker black rhizomes.
Picture of growth habit.
Inflorescence contain several spikes that are densely clustered into ovoid heads.
Close-up picture of 3-angled leaves near the base.
Illustration of Douglas' sedge. Le Hall, 2018.
Illustration of Douglas' sedge. USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York. Vol. 1: 363.