Eriocaulon aquaticum (Hill) Druce

Eriocaulon septangulare With. Veg. Brit. 784. 1776
?Cespa aquatica Hill, Herb. Brit. pi. 66. 1769. Nasmythia articulata Huds. Fl. Angl. ed. 2. 415. 1778. Eriocaulon pellucidum Michx. Fl. Bor. Am. 2: 166. 1803. Eriocaulon pumilum Raf. Atl. Jour. 121. 1832.
Nasmythia septangularis Mart. Nova Acta Acad. Leop. -Carol. 17: 58, pi. 2,f. 2. 1835. Eriocaulon articulatum Morong, Bull. Torrey Club 18: 353. 1891.
Eriocaulon aquaticum Druce, Pharm. Jour. IV. 29: 700. 1909. Not E. aquaticum Sagot, in syn. 1863.
Plants monoecious; stems very short; leaves tufted, thin-membranous or mostly pellucid, linear, plane, 1-18 (mostly 2-6) cm. long, 1-3.5 mm. wide at the middle, subulate-acute, fenestrately 3-8-nerved (the fenestrations conspicuous), glabrous; peduncles mostly solitary (rarely aggregate), 3.5-56 cm. long (to 3 m. long in deep water, according to Britton), 7-sulcate, usually not twisted, compressed in drying, mostly fenestrate, glabrous; heads hemispheric, loose-flowered, 3-5 mm. in diameter, compressed in drying, whitevillose at the summit ; involucral bractlets thin-membranous, gray-green or olivaceous, ovate or obovate, mostly rounded-obtuse, glabrous; receptacle glabrous; receptacular bractlets membranous, hyaline at base, grayish at apex, cuneate-obovate, acute or acuminate, pilose on the back toward apex; staminate florets: sepals 2, free, grayish, cuneate-spatulate, concave-navicular, more or less obtuse, very narrowly carinate-winged, puberulent at apex on the back or finally calvescent; petal-tube white, its lobes 2, pale-stramineous, equal, pilose, glanduliferous; pistillate florets: sepals 2, nigrescent (hyaline at base), cuneate-obovate, concave, truncate, slightly apiculate, very narrowly carinate-winged, pilosulous at apex on the back; petals 2, whitish, spatulate, obtuse, pilose, glanduliferous, equal when young, subequal when mature.
Type locality: In lakes on the Island of Skye, Scotland (Walker).
Distribution: In still water and on shores of ponds, Newfoundland to New Jersey, and westward to Ontario, Minnesota, and Indiana; also in the Hebrides and adjoining islands of northern Scotland and Ireland.