Columbian Sedge

Carex aperta and C. haydenii appear to be a very closely related, allopatric pair of species that may not be closely related to other members of the section. This species-pair is distinguished by the inflated perigynia, the acute scales that are longer than the perigynia, and the unique chromosome number. Carex aperta is distinguished from C. haydenii by its rhizomatous habit, the dull brown achenes, and the entire beak. It is sometimes mistaken for the sympatric taxa that also lack veins on the perigynia, C. aquatilis and C. scopulorum; mature specimens can easily be identified by the inflated perigynia.

Plants not cespitose. Culms acutely angled, 15–90 cm, scabrous. Leaves: basal sheaths red-brown; sheaths of proximal leaves with blades, backs glabrous, fronts with pale brown spots, veinless, glabrous, apex U-shaped, membranous, colorless; blades 3–6 mm wide. Inflorescences: proximal bract subequal to inflorescence, 2–4 mm wide. Spikes: erect; proximal 2–3 spikes pistillate, 1.5–3.5 cm × 4–6 mm, base obtuse; terminal 1–2 spikes staminate. Pistillate scales red-brown, longer than perigynia, apex acute or acuminate, awnless. Perigynia divergent, olive-brown with red-brown spots on apical 1/2, veinless, inflated, loosely enclosing achenes, obovoid, 2.5–2.8 × 1.5–2 mm, dull, apex rounded, papillose; beak green, 0.1–0.3 mm. Achenes not constricted, dull. 2n = 54.

Alta., B.C.; Idaho, Mont., Oreg., Wash.

Fruiting Jul–Aug.

Wet meadows; 0–900m.

Carex accedens T. Holm; C. acutina L. H. Bailey var. tenuior L. H. Bailey; C. aperta var. umbrosa Kükenthal; C. aperta var. viridans Kükenthal; C. stylosa C. A. Meyer var. virens L. H. Bailey; C. turgidula L. H. Bailey

Carex accedens Holm, Am. Jour. vSci. IV 16:457. 1903.
Carex stylosa var. virens L. H. Bailey, Proc. Am. Acad. 22: 79. 18S6. (Type is taken i from Mi.
Adams, Washington.) Carex spreta L. H. Bailey, Mem. Torrey Club 1: 6. 1S89. (Based on C. slylosa var trirt H I II
Bailey.) Not C. spreta Steud. 1855.
Strongly stoloniferous, the rootstocks stoutish, horizontal or ascending, scaly, purplishbrown, the culms 2.5-4 dm. high, stiff, stoutish, very sharply triangular, strongly roughened above, papillate, exceeding the leaves, phyllopodic, purplish-brown-tinged at base, the dried-up leaves of the previous year not very conspicuous, the lower leaves of the year all blade-bearing; leaves of the year with well-developed blades 4-5 to a fertile culm, on the lower fourth, erect, flat with revolute margins, elongate, not rigid, light-green, papillose, short tapering, 1-2.5 dm. long, 3-4 mm. wide, the sheaths, at least the lower, hispidulous and purplish-brown-tinged dorsally, white-hyaline ventrally, the ligule longer than wide; terminal spike staminate, or rarely gynaecandrous, sessile or nearly so, 1.5-2 cm. long, 5-6 mm. wide, the scales oblong-obovate, obtuse, purplish-black, with white midvein not extending to apex and minutely hyaline apex; pistillate spikes 2-4, closely aggregated or the lowest more or less distant, sessile or the lower one or two peduncled, oblong, 0.7-2 cm. long, 6-8 mm. wide, densely flowered, with 20-40 spreading-ascending perigynia in several to many rows; bracts not sheathing, the lowest leaflet-like, dark-auricled, 8 cm. long or less, much shorter than culm, the others much reduced; scales ovate or lanceolate-ovate, purplish-black with white midvein usually not extending to apex, not hyaline-margined, obtuse or acutish, much narrower and much shorter than perigynia; perigynia broadly obovoid or suborbicular, flattened, biconvex, scarcely inflated, 3 mm. long, 1.75-2.25 mm. wide, 2-ribbed (the marginal), otherwise nerveless, granular, subcoriaceous, resinous-dotted towards apex, olive-green, often purplish-dotted above, not serrulate, sessile, abruptly apiculate with a very minute, entire, dark-colored, straight beak 0.1-0.2 mm. long; achenes lenticular, oblong-obovoid, 2 mm. long, 1.25 mm. wide, nearly filling lower two thirds of perigynium, brownish, substipitate, abruptly apiculate, jointed with the slender, short-exserted style; stigmas 2, slender, whitish or in age yellowishbrown.
Type locality (of C. stylosa var. virens L. H. Bailey, on which C. accedens is based): "San vies Island, Oregon, and Mt. Adams, Washington territory, at 5000 feet, Howell."
Distribution: Rare and local, Mt. Adams and Mt. Rainier. Washington. (Specimens examined from both localities.) While Howell reports this mountain species from Sauvies Island, Oregon, and says it forms "part of the sedge pasturage of the Columbia." it is to be surmised thai he confused it with Carex aperla Boott, and that his labeling represents some mistake.

Carex aperta Boott, in Hook. Fl. Bor. Am. 2: 218. pi. 219. 1839
"Carex acuta var. prolixa Hornem." L. H. Bailev, Proc. Am. Acad. 22: 86. 1886.
Carex turgidula L. H. Bailey, Bot. Gaz. 25: 271. 1898. (Type from Stewart's Lake, British Columbia.)
Carex bovina Howell, Fl. NW. Am. 1 : 702. 1903. (Type from Columbia River, Oregon and Washington.)
Carex aperla f. hydroessa Holm, Am. Jour. Sci. V. 2 : 290. 1921. (Tvpe from Washington.)
Carex aperla f. mimetica Holm, Am. Jour. Sci. V. 2: 290. 1921. (Tvpe from Washington.) Cespitose and strongly stoloniferous, the rootstocks stout, woody, dark-pnrplish-brown, shining, scaly, soon ascending, the culms 3-10 dm. high, slender, stiff, sharply triangular, almost winged, strongly roughened above, much exceeding the leaves, papillate, brownish or slightly purplish-tinged at base, phyllopodic, the dried-up leaves of the previous year conspicuous; sterile shoots aphyllopodic; leaves of the flowering year with well-developed blades usually 3-5 to a fertile culm, towards the base, obscurely septate-nodulose, the blades erect, flat with slightly revolute margins, channeled towards the base, 1-4 dm. long, 2-5 mm. wide, light-green, thinnish but firm, short-tapering, very rough towards apex and on the margins, papillate, the upper longer, the lower leaves of the flowering year much reduced, the sheaths dull-white or yellowish-brown-tinged ventrally, very thin, rounded and smooth dorsally, the ligule about as long as wide; terminal spike staminate, peduncled (occasionally an additional sessile one at its base), linear, 2-3.5 cm. long, 3-4 mm. wide, the scales oblong-obovate, obtuse or acutish or short-cuspidate, reddish-brown with lighter 3-nerved center and hyaline margins; pistillate spikes 2 or 3, erect, sometimes staminate at apex, approximate or somewhat separate, sessile to slender-peduncled, the peduncles shorter than the spikes, the spikes oblong to linear-oblong, closely flowered or slightly attenuate at base, 1-5 cm. long, 5 mm. wide, (excluding scales), containing 25-75 spreading-ascending perigynia in several rows; lowest bract leaf -like, not sheathing, about equaling culm; the upper much reduced, dark-auricled ; scales lanceolate, acuminate or sharply acute, usually strongly exceeding but sometimes only equaling perigynia, but much narrower, purplish-black, with lighter center and obscure hyaline margins; perigynia obovoid-orbicular, flattish, unequally biconvex, inflated at maturity, 2.75-3.25 mm. long, 1.5-2 mm. wide, 2-ribbed (the marginal), otherwise nerveless, olive-green, becoming straw-colored, rarely dark-tinged, membranaceous, puncticulate, sparingly yellowglandular, rounded to a substipitate or stipitate base, very abruptly contracted (almost truncate) into an emarginate or shallowly bidentate beak 0.5 mm. long; achenes lenticular, suborbicular, 1.5 mm. long, nearly as wide, yellowish-brown, loosely enveloped, in lower half of perigynia, broadly substipitate, abruptly short-apiculate, jointed with the straight slender style; stigmas 2, slender, rather short.
Type locality: "Hab. Columbia River. Douglas. Scouler."
Distribution: Swampy meadows and low grounds, British Columbia to northern Oregon, and along the larger rivers to western Montana. (Specimens examined from Oregon, Washington, British Columbia, including Vancouver Island, Idaho, Montana.)

Carex aperta, known as Columbian sedge, is a species of sedge that was first described by Francis Boott in 1839. It is native to eastern Russia, northern China, western Canada, and the northwestern United States. It grows in wet meadows, along shorelines, and in other wet habitats.