A. arvensis: annual; stems procumbent, 1/2-1 foot long; leaves opposite, broadly ovate, sessile, entire, dotted beneath, flowers bright red, occasionally pink, or white. - Shepherd's Weather-glass. - A common cornfield weed. Fl. June to August.

A. tenella: stems slender, procumbent, and rooting, only a few inches long; leaves small, orbicular, opposite; flowers pale pink, on long, slender pedicels, the corolla narrow-cam-panulate, of delicate texture. - Wet mossy banks and bogs. Fl. July, August.