BITTERROOT (Lewisia rediviva), a North American plant of the purslane family (Portulacaceae), native to mountain regions from Montana to British Columbia and southward to Colorado, Arizona and southern California. Crowning its stout root is a thick perennial rootstock from which rise small fleshy leaves and short, jointed stalks each bearing a beautiful rose-red, cactus-like flower, 2 in. or more across. In early spring the flowers bloom in immense numbers in stony soil on ridges and in alpine valleys. The large starchy tap root was highly esteemed for food by the Indians. The plant became known to science from specimens collected by Meriweather Lewis (q.v.), of the Lewis and Clark expedition (18o6–o7), and the botanical genus Lewisia was named in his honor by Frederick Pursh (q.v.). The Bitterroot river and the Bitterroot mountains in Montana are named after this plant, which has been chosen the State flower.