In the flora area, Scleranthus perennis is probably best established in Wisconsin; R. A. Schlising and H. H. Iltis (1961) reported it from four counties there, the first collection made in 1928.
Another Eurasian sp., is established in s.c. Wis. and may be expected elsewhere in our range. It differs in its perennial habit and its obtuse or rounded sep with a conspicuous white-scarious border 0.3-0.5 mm wide near the tip.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.