Photograph from Lewis and Clark Herbarium/Academy of Natural Sciences
Disc Mayweed (Pineapple-Weed)
June 9, 1806, at Camp Chopunnish, Idaho County, Idaho.
Pineapple-weed is a member of the aster family (family Asteraceae) which includes herbs, sometimes shrubs or vines, rarely trees, with simple or compound, alternate or opposite leaves. Flowers small, but organized into larger heads resembling a single, radially symmetrical flower cupped by a ring of green bracts.