Plant: Perennial, submersed rhizomatous herb; Rhizome stout, extensively creeping and branching; fertile stem (stolon) 2-3 mm in diameter Leaves: 2 per node of stolon, usually unequal, coarsely undulate dentate, to ca. 15 cm in diameter INFLORESCENCE: umbels at leaf bearing nodes Flowers: yellow, on pedicels 6 cm or more long; corolla 2-2.5 cm long; floating or elevated above the water; buds submerged; corolla rotate, deeply lobed, the lobes fringed and bearing a glandular appendage near the base; ovary ellipsoid, the apex tapering to the short style; stigma 2 lobed, persistent Fruit: a tardily dehiscent, submerged, capsule; SEEDS smooth to papillate, the coat hard, flat, narrowly winged, ciliate on the margins Misc: ponds, lakes and slow flowing streams; 1100 m (3600 ft); Sep-Oct REFERENCES: Mason, Charles T., Jr. 2001. Iridaceae. J. Ariz. - Nev. Acad. Sci. Volume 33(1).
Stems stout, commonly 2-3 mm thick, bearing a pair of opposite, usually unequal lvs subtending the umbel, often extended and bearing additional umbels; lvs subrotund, 5-15 cm long and wide; fls heterostylic; cor bright yellow, 2-2.5 cm, its lobes somewhat fringed below; anthers 4-5 mm; fr 12-25 mm, strongly beaked; seeds flat, the margin ciliate and narrowly winged; 2n=54. Native of Europe, intr. in quiet waters here and there in our range. June-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.