Plants usually aquatic, occasionally emergent. Rootstock nearly globose, 2-lobed. Leaves ± deciduous, bright green to reddish green, pale toward base, spirally arranged, to 25(--40) cm, pliant, gradually tapering toward tip. Velum covering less than 1/2 of sporangium. Sporangium wall ± brown-streaked. Megaspores white, 400--550 μm diam., echinate with thin, sharp spines; girdle obscure. Microspores gray to light brown in mass, 20--30 μm, smooth to spinulose. 2n = 22.