Carex lenticularis var. impressa
Syst. Bot. Monogr. 7: 65. 1985.
Culms 15–60 cm. Leaf-blades 2–3.5 mm wide. Inflorescences: peduncle of proximal spike 1 cm; proximal bract redbrown at base, 1–3 mm wide. Spikes: proximal 3–5 spikes pistillate, 1.5–3.6 cm × 3–4 mm; terminal spike staminate. Pistillate scales redbrown or black. Perigynia with purple-brown spots on apical 1/2, 1–3 veins abaxially, ellipsoid or ovoid, 1.8–2.5 × 1.1–1.5 mm; stipe 0.2 mm; beak redbrown, 0.2–0.5 mm. 2n = 92.
Phenology: Fruiting Aug.
Habitat: Seasonally flooded river and lakeshores
Elevation: 1200–3000 m
Calif., Idaho, Oreg., Wash.
Primarily a taxon of the Sierra Nevada and southern Cascade Mountains, Carex lenticularis var. impressa tends to have smaller perigynia with fewer veins and more red-brown pigmentation than does the more widespread var. lipocarpa.
"prolonged" is not a number.