Protologue Description: **J. EFFUSUS, var. costulatus n. var., caulibus gracilibus 0.4-1.2 m. altis basi 1.5-4 mm. diametro valde costulatis; cataphyllis basilariis chartaceis purpurascentibus vel fulvescentibus supremis griseostramineis basi purpurascentibus 0.5-2 dm. longis; inflorescentia laxa vel subcongesta 1-7.5 cm. diametro; sepalis petalisque subaequalibus 2.2-3 mm. longis subrigidis lanceolato-attenuatis stramineis; capsulis fulvis vel olivaceis retusis perianthium aequantibus vel eo paulo brevioribus.
Culms slender, 0.4-1.2 m. high, 1.5-4 mm. in diameter at base, strongly costulate: basal sheaths papery, purplish or reddish-brown; the upper grayish-stramineous, purplish at base, 0.5-2 dm. long: inflorescence lax or somewhat crowded, 1-7.5 cm. in diameter: sepals and petals subequal, 2.2-3 mm. long, rather rigid, lance-attenuate, stramineous: capsule reddish or olivaceous, retuse, equaling or but slightly shorter than the perianth.-QUEBEC, Prince Edward Island and Nova Scotia to South Carolina. The following, of many numbers examined, are characteristic. QUEBEC: vicinity of Cap à L’Aigle, August 18, 1905, J. Macoun, no. 68,858. PRINCE EDWARD ISLAND: fresh or slightly brackish reclaimed marshes along Hillsborough River, Mt. Stewart, July 30, 1912, Fernald, Bartram, Long & St. John, no. 7164; damp border of heath-barren, Lot 40, August 8, 1914, Fernald & St. John, no. 10,985. NOVA SCOTIA: low ground, Sydney, August 17, 1902, Fernald; wet sphagnous spruce bog near Louis Lake, Port Joli, August 17, 1920, Fernald, Long & Linder, no. 20,661; boggy barrens near Clement Pond, Barrington, August 9, 1920, Fernald, Long & Linder, no. 20,654 (TYPE in Gray Herb.); spruce and red maple swamps by Trefey’s Lake, Arcadia, July 29, 1920, Fernald & Long, no. 20,653. MAINE: border of salt Marsh, Wells, August. 8 1916 Fernald & Long, no. 13,192 NEW HAMPSHIRE: by brook, East Andover, August 13, 1903, M. A. Day. MASSACHUSETTS: swale near Zion's Hill, Winchester, July 15, 1913, Ferrnald, no. 9173; sandy shore of Clear Pond, Lakeville, August 26, 1913, Fernald & Long, no. 9180; thin sphagnous peat overlying sand, Wareham, October 2, 1913, Fernald & Long, no. 9187; small quagmire in woods south of Sparrow Young’s Pond, Chatham, July l5, I918, Fernald, no. 16,538; boggy swale, Orleans, July 22, 1919, Fernald & Long, no. 18,202; border of cattail marsh, South Truro, August 10, 1919, Fernald & Long, no. 18,203; along Look's Brook, West Tisbury, Martha's Vineyard, July 26, 1916, F. C. Seymour, no. 1146; gutters in slightly sandy soil, Worthington, August 12, 1912, B. L. Robinson, no. 516. RHODE ISLAND: wet open sphagnous thickets, southwest of Harbor Pond, Block Island, August 19, 1913, Fernald & Long, nos. 9176, 9177. NEW JERSEY: Bear Swamp, Lawrenceville Sta., Mercer Co., June 20, 1913, Bartram. PENNSYLVANIA: Bush Hill Falls, Monroe Co., July 10-14, 1903, Stone, no. 5392 SOUTH CAROLINA: Florence, May 18, 1912, Bartram.