[minnesotawildflowers.info] Leaf & Stem Description: Leaves are simple and opposite, narrowly lance-elliptic, 3/8 to 1½ inches long and to 3/8 inch wide, pointed or blunt at the tip, rounded or narrowed at the base, stalkless, toothless, and hairless except for short, stiff hairs around the edges. The lowest leaves are largest, becoming somewhat smaller and narrower as they ascend the stem. Leaf pairs are at right angles to the pair above and below. Stems are usually multiple from the base, erect to ascending or prostrate but rising at the tip (decumbent), unbranched, typically tinged reddish and are covered in minute, soft hairs. (link added by Mary Ann Machi)