Leaf blades not especially fleshy. Petals rarely aborted. Fruits 4-angled, 16-26 × 3-5 mm; terminal segment 4-angled, apex usually blunt, (flattened), relatively long. 2n = 18.

Flowering May-Oct. Great Lakes beaches; ca. 0 m; Ont.; Ill., Ind., Mich., N.Y., Ohio, Pa., Wis.

Variety lacustris is sometimes sympatric with var. edentula; hybridization has not been demonstrated.

This plant is restricted to the beach area of Lake Michigan. It was formerly frequent along the beach but at present much of the beach area is within city limits or is used by children as play grounds during the summer months. The plant, consequently, has become very rare and in time will probably become extinct.