Plants densely to loosely cespitose; rhizomes short, no more than 10 cm. Culms trigonous in cross section, 40-100 cm, scabrous-angled distally. Leaves: basal sheaths reddish purple; ligules longer than wide; blades pale to mid green, flat to W-shaped, 3.5-9 mm wide, glabrous. Inflorescences 6-25 cm; proximal bract 15-40 cm, exceeding inflorescence; proximal 3-4 spikes pistillate, erect or the proximal spreading; terminal 1-2 spikes staminate. Pistillate scales ovate, obtuse to acuminate, 2-4.4(-5.1) × 0.7-1.3 mm, shorter than perigynia, margins erose, apex contracted, scabrous-awned, awn mostly shorter than body. Staminate scales scabrous-awned, sometimes also ciliate-margined. Perigynia ascending, ca. 13-25-veined, veins separated by 3+ times their width, confluent at or proximal to mid beak (except for 2 prominent lateral), narrowly elliptic, 3.1-4.8 × 0.9-1.5(-1.8) mm, herbaceous, apex tapered; beak 0.9-1.8 mm, smooth, bidentulate, teeth straight, 0.4-0.9 mm. Stigmas 3. Achenes yellow to pale brown, trigonous, smooth.

Fruiting May-Aug. Stream banks, springheads, seeps, wet meadows; 1100-1800 m; Ariz.; Mexico.

Common Name: Thurber's sedge

Duration: Perennial

Nativity: Native

Lifeform: Graminoid

General: Densely to loosely tufted perennial from short rhizomes no more than 10 cm, stems three sided in cross section, 40-100 cm, scabrous-angled near tips.

Vegetative: Basal sheaths reddish purple, with ligules that are longer than wide, blades pale green to green, flat to w-shaped, 3.5-9 mm wide, glabrous.

Inflorescence: Basal bract 15-40 cm, exceeding inflorescence, overall 6-25 cm tall, basal 3-4 spikes pistillate, erect or the lower ones spreading, terminal 1-2 spikes staminate; pistillate scales ovate to obtuse and acuminate, 2-4.5 mm long by 0.5-1.5 mm wide, shorter than perigynia, margins erose, to contracted apex with scabrous awn, awn shorter than body, staminate scales scabrous awned also, sometimes also ciliate margined; perigynia ascending, about 13-25 veined, veins separated by 3 times their width, confluent at or basal to mid beak, narrowly elliptic, 3-5 mm long, 1-1.5 mm wide, to a tapered apex, beak 1-2 mm long, smooth, with straight teeth less than 1 mm; achenes yellow to pale brown, three sided and smooth.

Ecology: Found in moist soil of stream banks, seeps, springs and wet meadows from 3,500-6,000 ft (1067-1829 m); flowers May-August.

Notes: This species is closely related to Carex hystericina, but is far more common in southern Arizona. See notes under Carex hystericina for distinguishing characters between the two. It is distinguished from Carex lenticularis and C. senta by having inflated perigynia and 3 stigmas, while they both have flattened perigynia and 2 stigmas. Carex ultra is a more robust plant with stiff coriaceous leaves with rough edges, and its perigynia are widest near the top, while those of C. thurberi are widest at the base. (Notes: Max Licher and Glenn Rink 2012)

Ethnobotany: Unknown

Etymology: Carex is the classical Latin name for the genus, while thurberi is named for Dr. George Thurber 91821-1890) an American botanist and horticulturalist who was the botanist for the Mexican Boundary Survey of 1850-1854.

Synonyms: None

Editor: SBuckley, 2010