Asteraceae : Prenanthes racemosa
Rattlesnake root is an unusual plant adding interest to pond shoreline gardens and wetland restoration projects. Its flowers attract native bees and moths.
Description
Prenanthes racemosa is a perennial herb that grows from a fibrous root system with simple erect stems that have milky sap and are 30–150 cm tall. The stems have long, coarse hairs above and no hairs below. The leaves are simple, alternate, with the basal and lower cauline leaves ovate, petiolate, 7–40 cm long and up to 10 cm wide, with entire to toothed margins. The upper leaves becoming lanceolate and sessile. The inflorescence consists of heads arranged in racemes to narrow panicles. The heads with an involucre that is narrowly campanulate, 11–12 mm high, with bracts arranged in 2 rows that are purplish and variously hairy. The outer row of bracts is short, and the inner row is linear-lanceolate with a scarious margin. Each head contains 9-29 white to pink to purple ray flowers, the ligule 7–13 mm long. Fruit is an achene with 8-12 ribs and a pappus of numerous deciduous bristles. Rattlesnake root blooms in August and September in damp open prairies, meadows and along stream banks in eastern and western South Dakota.