Bidens aristosa, Britton Native. Annual or biennial. Propagates by seed.

Time of bloom: August to October.

Seed-time: September to November.

Range: Ohio and Michigan to Minnesota, southward to Mississippi and Louisiana. Habitat: Prairies, moist meadows, swamps, banks of streams, and ditches.

Stem one to three feet tall, slender, and much branched. Leaves pinnately five- to seven-lobed, the segments slenderly lance-shaped, pointed at both ends, sharply cut and toothed, slender-petioled, softly hairy on the under side; upper leaves with fewer lobes on very short petioles, or lance-shaped and sessile. Heads numerous, one to two inches broad, on slender peduncles, in loose, open clusters; outer bracts of the involucre eight to ten, linear or spatu-late, not exceeding the inner row; rays six to ten, broad, obtuse, bright golden yellow. Achenes obovoid, flat, rough-hairy, tipped with two (occasionally four) slender, diverging awns, sometimes as long as the achene itself or sometimes reduced to short teeth; the barbs on the awns and on the sides of the achenes are on some directed downward, on others upward. (Fig. 332.)

Means of suppression the same as for Bidens frondosa.