September 19, 1804, at Big Bend, Missouri River, south of Pierre, South Dakota.
Many slender green branches form a round shrublet with hundreds of tiny yellow flower heads in loose clusters. Flower heads narrow, 0.1-0.3 in (0.3-0.8 cm) long, with 3-7 ray flowers, each about 0.1 in (0.3 cm) long, and 2-6 tiny disk flowers. Height: 6-36 in (15-90 cm).
In deserts, on plains, and among piñon and juniper.
From eastern Oregon and southern Idaho to southern California; east to Texas and the western Plains as far north as central Canada; also Mexico.
As with many aromatic plants, this species was used medicinally, occasionally as a treatment for snakebite; hence the name snakeweed. Bundled, dried stems made primitive brooms, hence broom.