Prenanthes racemosa Michx.
purple rattlesnake-root (purple rattlesnakeroot)
Asteraceae (Aster family)

Introduction to Vascular Plants


© Jamie Fenneman     (Photo ID #23090)


E-Flora BC Static Map

Distribution of Prenanthes racemosa
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Species Information

Perennial herb from a slightly thickened taproot; stems erect, solitary, branched above, soft-hairy above, glabrous and glaucous below, often purplish, exuding milky juice when broken, 0.5-1.2 m tall.
Basal leaves oblanceolate to egg-shaped or elliptic, long-stalked, blades toothed to entire, glabrous, 7-40 cm long, 1.5-10 cm wide; stem leaves similar below, middle and lower ones with winged stalks, becoming short-stalked or unstalked and clasping, reduced upwards.
Heads with strap-shaped flowers, numerous in a dense, spikelike inflorescence; involucres 9-14 mm tall; involucral bracts lance-oblong, 10-14, densely stiff-hairy, purplish to blackish; ray flowers pink or purplish.
Achenes nerved, cylindric, glabrous; pappus of yellowish or brownish hairlike bristles.
This species was last collected in 1946 at Dawson Creek.

SourceThe Illustrated Flora of British Columbia


If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Habitat and Range

Dry grassy slopes in the montane zone; rare in NE BC, known only from Dawson Creek and Pouce Coupe; E to PQ and ME, S to IA, WY and CO.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Prenanthes racemosa subsp. mulitflora Cronquist