Aquatic Sedge

Carex aquatilis Wahl. Sv. Vet.-Akad. Xya Handl. 24: 165. 1803
Neskiza aquatilis Raf. Good Book 27. 1840. (Based on Carex aquatilis Wahl.) Carex slans Drejer, Nat. Tidsk. 3: 458. 1841. Type from Greenland.) Carex borealis O. F. Lang, Flora 26: 142. 1843. 'Type from Norway.) Carex aquatilis var. elatior Bab. Man. 341. 1843. (Type from Clova, Scotland.) Carex aquatilis var. planifolia F. Nyl. Spic. Fl. Fenn. 2: 23. 1 844. (Type from Finland.) Carex aquatilis var. sphagnophila Fries (Summa Veg. Scand. 72, name only. 1845); Anderss. Cyp. Scand. 46. 1849. (Type from Lapland.) Carex aquatilis var. virescens Anderss. Cyp. Scand. 46. 1849. (Type from Scandinavia.)
Carex aquatilis var. cuspidata Laest.; Anderss. Cyp. Scand. 46. 1849. 'Type from Scandinavia.)
Carex aqualilis var. minor Boott, 111. Carex 163, in part. pi. 543; pi. 545, f. 1. 1867. (Regarded
as based on C. starts Drejer.) Carex aquatilis var. slans Boott, 111. Carex 163, pi. 544; pi. 545, f. 2. 1867. (Based on C. starts
Drejer.) Carex aquatilis var. genuina Syme, Engl. Bot. ed. 3. 10: 113. pi. 1641. 1870. (Based on C. aquatilis Wahl.) Carex aquatilis var. Watsoni Syme, Engl. Bot. ed. 3. 10: 113. pi. 1642. 1870. (Type from Lanarkshire, Scotland.) "Carex limula Fries" Olney, in S. Wats. Bot. King's Expl. 367. 1871. (Plants from Colorado
and Utah.) Carex aquatilis var. W. Boott, in Rothr. Bot. Wheeler's Surv. 277. 1878. (Type from Twin Lakes,
Colorado.) "Carex aquatilis var. epigeios Laest." Hartm. f. in Hartm. Skand. Fl. ed. 11. 467. 1879. (Plant
from Scandinavia.) "Carex elylroides Fries" Lange, Consp. Fl. Groenl. 147. 1880. (Plant from Greenland.) "Carex hyperborea Drejer" Holm, Nov.-Zeml. Veg. 17. 1885. (Plant from Nova Zembla.) "Carex stricla Lam." L. H. Bailey, in Coult. Man. 385. 1885. (Plant from Colorado.) Carex aperta var. divaricata L. H. Bailey, in Coult. Man. 385. 1885. (Type from Colorado.) Carex variabilis L. H. Bailey, Mem. Torrey Club 1:18. 1889. (Type from Colorado.) Carex variabilis var. elatior L. H. Bailey, Mem. Torrey Club 1 : 19. 1889. (Type from Canon City,
Colorado.) "Carex aquatilis f. epigaea Laest." Kurtz, Bot. Jahrb. 19: 47S. 1894. (Plant from Siberia.) Carex variabilis var. altior Rydb. Mem. N. Y. Bot. Gard. 1 : 76. 1900. (Based on C. variabilis var.
elatior L. H. Bailey.) Carex variabilis var. sciaphila Holm, Am. Jour. Sci. IV. 16 34. 1903. (Type from Colorado.) "Carex acutina L. H. Bailey'' Holm, Am. Jour. Sci. IV. 16: 34. 1903. (Plant from Colorado.) Carex acutina var. petrophila Holm, Am. Jour. Sci. IV. 16: 35. 1903. (Tvpe from Colorado.) Carex rhomboidea Holm, Am. Jour. Sci. IV. 16: 35; 29./. 8-10. 1903. (Type from Colorado.) Carex vulgaris var. hydrophila Holm, Am. Jour. Sci. IV. 17: 308. 1904. (Type from Colorado
Creek, Yukon.) Carex sphacelata Holm, Am. Jour. Sci. IV. 17: 309. 1904. (Type from Colorado Creek, Yukon.) Carex chionophila Holm, Am. Jour. Sci. IV. 17: 310. 1904. (Type from West Dawson, Yukon.) Carex limnocharis Holm, Am. Jour. Sci. IV. 17: 311. 1904. (Type from Klondike River, Yukon.) Carex aquatilis i. angustata Kukenth. in Engler, Pflanzenreich 4-°: 309. 1909. (Tvpe from Scotland.) Carex aqualilis f. virescens "Anderss." Kukenth. in Engler, Pflanzenreich 4 20 : 309. 1909. (Based
on C. aqualilis var. virescens Anderss.) Carex aqualilis f. cuspidata "Laest." Kukenth. in Engler, Pflanzenreich 4 20 : 309. 1909. (Based on
C. aquatilis var. cuspidata Laest.) Carex aqualilis var. substricta Kukenth. in Engler, Pflanzenreich 4-°: 309. 1909. (Type from eastern
North America.) Carex aquatilis var. substricta f. laxa Kukenth. in Engler, Pflanzenreich 4 :o : 311. 1909. (Type
from northern Labrador.) Carex aquatilis var. slans f. sciaphila Kukenth. in Engler, Pflanzenreich 4-°: 311. 1909. (Based
on C. variabilis var. sciaphila Holm.) Carex Goodenovii var. hydrophila M. E. Jones, Bull. Univ. Mont. 61: 72. 1910. (Based on C. vulgaris var. hydrophila Holm.)
Cespitose in large or small clumps, sending forth long, slender, brownish, scaly, horizontal stolons, the culms erect, rather slender, 2-8 dm. high, obtusely triangular below, more sharply triangular above, papillate, smooth throughout or somewhat roughened above, exceeding the leaves, phyllopodic, reddish-tinged at base, the dried-up leaves of the previous year usually conspicuous; sterile shoots phyllopodic; leaves with well-developed blades usually 7-12 to a fertile culm, on the lower third or fourth, the upper not bunched, the blades flat, or channeled at the base, light-green or glaucous-green, papillate, long-tapering, erect-ascending, usually 2-4 dm. long, 2.5-5 mm. wide, roughened towards the apex, the sheaths more or less strongly septate-nodulose, slightly hispidulous dorsally, thin and quickly ruptured ventrally, whitish or often purplish-dotted, the ligule longer than wide ; staminate spikes 1 or 2, the upper peduncled, 1-2.5 cm. long, 2-3 mm. wide, the lower usually smaller, nearly sessile and often pistillate at base, the scales oblong-obovate, obtuse or acutish, purplish-black to brown with lighter midrib and narrow hyaline margins (often obsolete) ; pistillate spikes 2-4, the upper occasionally staminate at apex, the lowest often strongly separated, the upper approximate, all erect and from short-peduncled (the upper) to strongly peduncled (the lowest), the peduncles usually shorter than the spikes, the spikes linear to oblong, 1-4 cm. long, 2.5-4 mm. wide, densely flowered or somewhat attenuate at base, the perigynia 20-100, erect-appressed in several to many rows; bracts sheathless, often with blackish auricles at base, reduced upwards, the lowest leaflet-like, normally exceeding, but sometimes somewhat shorter than the culm; scales ovate to oblong-ovate, 1-2 mm. wide, short-acuminate to obtuse, narrower than and from much shorter to longer than the perigynia, blackish with lighter midrib and scarcely developed hyaline margins, not puncticulate and not enveloping perigynia; perigynia much flattened, unequally biconvex, not at all turgid, oval to obovate, 2.5-3 mm. long, 1.25-1.75 mm. wide, 2-ribbed (the marginal), otherwise nerveless or very nearly so, puncticulate, glandular-dotted, membranaceous, light-green, rounded and substipitate at base, smooth above, rounded at apex and abruptly apiculate, the beak entire, 0.1-0.3 mm. long, more or less dark-colored; achenes lenticular, broadly obovate, 1.5-1.75 mm. long, 1-1.25 mm. wide, nearly filling lower two thirds of perigynium, yellowish, broadly substipitate, abruptly short-apiculate, jointed with the short, straight, slender, often somewhat exserted style; stigmas 2, slender, whitish, blackish in age.
Type locality: "Hab. infra ripas fluviorum per Lapponiam."
Distribution: Swampy places, in calcareous or non-acid soils, Greenland to northern Alaska, and southward to Quebec, and in the western mountains to New Mexico and eastern California; also widely distributed in northern Eurasia. (Specimens examined from Ellesmereland, King William Land, Labrador, Ungava, Keewatin, Mackenzie, Yukon, Alaska, Manitoba, Alberta, British Columbia, including Vancouver Island, Washington, Idaho, Montana, Wyoming, Colorado, New Mexico, Utah, Nevada, Oregon, California.)