General:
Perennial herb from a rhizome; stems erect, numerous, branched, 1-3 m tall, reddish-brown.
Leaves:
Basal leaves lacking; stem leaves alternate, 10-15 cm long, the blades egg-shaped to more or less round, the bases rounded or squared off, the tips abruptly pointed, long stalked; stipules short, tubular, entire, usually deciduous.
Flowers:
Inflorescence of numerous flowers in many panicles; perianths whitish or greenish-white, about 2 mm long at anthesis, 5-lobed nearly to the base.
Fruits:
Achenes, 3-angled, black, smooth and shiny, 2.5-3 mm long.
Notes:
Easily confused with P. sachalinense.
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.
Illustration Source: The Illustrated Flora of British Columbia