15 cm ruler in above photo
Erect perennial with opposite, lanceolate, serrate, sessile leaves. Leaf in above photo was 6 cm long and 1.5 cm wide. Small white flowers in clusers in leaf axils. We measured a flower at 4 mm diameter and 6 mm long. Calyx lobes are narrow, acute, typically 4 mm long. Stems sparsely hairy, leaves pubescent with very short hairs on top and bottom. Stems are square in profile.
Very similar in appearance to L. virginicus. As noted above, L. asper has narrow, acutely pointed lobes of its sepals (outer floral ring), while L. virginicus has sepals which are ovate and blunt.
Common. Habitat is stream banks, swamps, and other wet areas.
Height is listed in Budd's Flora from 30 to 50 cm, the plant in the above photo was 37 cm tall.
The above photos were taken July 21st, in a fen bordering the Qu' Appelle Lakes, about 140 km east of our home in Regina, SK.