Matricaria discoidea, long known as Matriacria matricarioides, is an alien species introduced from Europe. Leaves are finely divided and give off an odor of pineapple when crushed. Flowers are arranged in tight heads, totally lacking ray flowers (the larger flower head in the photo above is in flower--it doesn't get any showier than this).

This species is an annual which usually means that seeds germinate in spring or early summer, the plant grows to maturity, flowers, produces new seeds and then dies, all in one growing season. It is sometimes also a "winter annual" wherein plants which germinate in late summer or fall and have not yet flowered in the fall can overwinter and finish their life cycle during the next growing season (see photo above, far right).