PLANT: Perennial, submersed rhizomatous herbs with thin petiole-like branches (stolons) bearing 1 to several nodes. LEAVES: floating, suborbicular, 1 or 2 per node of stolon. INFLORESCENCE: umbels at leaf bearing nodes. FLOWERS: 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. REFERENCES: Mason, Charles T., Jr. 2001. Iridaceae. J. Ariz. - Nev. Acad. Sci. Volume 33(1).
Fls white or yellow, perfect or often functionally unisexual; cal parted nearly to the base into oblong lobes; cor broadly campanulate or subrotate, deeply lobed, often hairy or with a glandular appendage near the base of each lobe within; ovary tapering to a short style, or the broad, 2-lobed, persistent stigma virtually sessile; fr firm-walled, indehiscent or eventually rupturing irregularly; rhizomatous aquatic herbs with broad, cordate, floating lf-blades, some lvs long-petiolate and arising directly from the rhizome, others short-petiolate and arising from slender, petiole-like stems that also bear one or more bracteate umbels above, so that the infl may appear to arise a little below the top of a long petiole. (Limnanthemum) 20, widespread.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.