Decumbent perennial, rhizomatous and rooting at the lower nodes; stem glandular-hairy, to 8 dm; lvs 2-8 נ1-4 cm, ovate or lance-ovate, acute, mostly sessile, the lowermost short-petiolate; fls in open, leafy, terminal cymes; pedicels 1-3 cm, eventually reflexed; sep lance-ovate, acute to obtusish, glandular-hairy, 5-6 mm (to 9.5 mm in fr); pet much exceeding the sep; styles normally 5; fr ovoid, dehiscent by 5 valves, each valve notched or shortly 2-cleft at the tip; seeds 0.7-0.8 mm, orbicular-reniform, strongly papillate; 2n=28. Native of Europe, intr. as a weed in wet and waste places; Que. and Ont. to Minn., s. to N.C., Mo., and Kans. May-Nov. (Alsine a.; Myosoton a.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.