A. Ptarmica: stems erect, glabrous, 1-2 feet high, nearly simple; leaves broadly linear, regularly serrate; flower-heads few, in a loose terminal corymb; florets of the ray 10-15, short, broad, white. - Sneezewort. - Moist hilly pastures. Fl. July, August.

A. Millefolium: stems numerous, short, leafy, the flowering ones erect, almost simple, about one foot high; leaves oblong or linear, finely cut into a multitude of short, narrow, deeply pinnatifid segments; flower-heads numerous, small, ovoid, in a dense terminal corymb; the ray-florets 5-6 in each head, white or pink. - Milfoil or Yarrow. - Pastures, meadows, and waste places. Fl. June to August.