Culms to 28 cm. Floral scales brown, streaked with green on flanks. Flowers: perianth bristles to 2 times as long as achene, rarely shorter than achene. Achenes green to golden brown when ripe, 0.5-1.1 × 0.4-0.8 mm, apex often highly constricted proximal to tubercle. Tubercles 0.3-0.7 × 0.2-0.4 mm. 2n = 20. Fruiting summer-winter (Jun-Nov). Bogs, cold springs, dry stream banks, lake and pond margins, maritime mud flats, marshes, moist meadows, swamps; 0-1000 m; N.B., N.S., Ont., Que.; Ark., Conn., Del., Fla., Ga, Ill., Ind., La., Maine, Md., Mass., Mich., Minn., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tex., Vt., Va., Wis. Eleocharis flavescens var. olivacea was reported from Hawaii; I have not seen a voucher specimen.