Yarrow/Milfoil
 

Achillea millefolia
A hairy stemmed 1-3' plant. The soft, aromatic leaves are very highly dissected and fern-like. (The species name millefolia means "thousand-leaved", referring to the very numerous linear leaf segments.) The tiny 1/6" flower heads are in dense, flat-topped clusters. The 5-10 rays are white or rose-colored and the disc is yellow. Blooms June-November in waste places, fields, roadsides.

Was used medicinally to produce sweating and therefore "break" a fever. Poultices were used for skin rashes.