Carex sect. Inflatae
in H. G. A. Engler, Pflanzenr. 20[IV,38]: 96. 1909.
Plants cespitose, short-rhizomatous. Culms brown at base. Leaves: basal sheaths not fibrous; sheath fronts membranous; blades filiform, glabrous. Inflorescence 1 spike; bractless; spike androgynous, dense, with 15+ perigynia. Pistillate scales persistent, less than 10 mm, apex obtuse, acute to acuminate, rarely awned. Perigynia eventually spreading, usually veinless, inflated, stipitate or sessile, elliptic or broadly elliptic, rounded-trigonous in cross section, (4–)4.5–10 mm, usually not more than 2 times as long as wide, base rounded, margins rounded, apex abruptly beaked, glossy, glabrous; beak less than 2 mm, entire to erose. Stigmas 3. Achenes trigonous, smaller than and loosely enveloped by the bodies of perigynia; style deciduous.
Alpine regions of w North America.
Species 3 (3 in the flora).
Additional characters of the floral scale and the perigynia are important in recognizing members of Carex sect. Inflatae. The floral scales are brown with hyaline margins, ovate, and papery. The perigynia are pale brown at the base and dark brown distally, inflated although flattened when dry, glossy, membranous, and glabrous.
|1||Inflorescences 1.4–2.5 cm; pistillate scales 3–5-veined with thick, white median portion, shorter and narrower than perigynia; perigynia broadly elliptic with short veins on angles and faces.||Carex breweri|
|1||Inflorescences 0.7–2 cm; pistillate scales 1-veined with narrow, yellow-brown median portion, equaling perigynia in width; perigynia elliptic, veinless.||> 2|
|2||Perigynia 3–5 × 1.5–2.5 mm, base rounded, sessile; pistillate scales acute, involute, appearing acuminate.||Carex engelmannii|
|2||Perigynia 2.5–3.5 × 1.5 mm, base narrowly cuneate, stipitate; pistillate scales obtuse or acute, not inrolled.||Carex subnigricans|