Burke: Polygonum parryi vs. Polygonum paronychia

	Polygonum parryi	Polygonum paronychia
	Parry's knotweed, prickly knotweed	beach knotweed, black knotweed
Habit		Low, spreading shrub-like perennial here in Washington - typically less than 30 cm., though can get up to 100 cm. tall in some parts of its range.
Leaves		Alternate, simple, narrow, 1-2 cm long, with prominent midrib.
Flowers		Small pinkish or whitish, 5-6 mm long, with 5 parts; in small clusters along stem.
Fruits		Shiny black achenes 4-5 mm long.

	Polygonum parryi	Polygonum paronychia
Identification notes		Can be separated from other Polygonum species by its perennial decumbent stems, lacerate hyaline stipules, axillary flower clusters, and coastal habitat.
Flowering time	June-July	April-September
Habitat	Vernal pools, seasonally damp ground at low elevations.	Coastal shorelines and sand dunes.
Distribution	Occurring in the east end of the Columbia River Gorge in Washington; south-central Washington to California. [WildflowerSearch map] [BONAP county map]	Occurring west of the Cascades crest along the coast; Vancouver Island, B.C., south to Monterey, California. [WildflowerSearch map] [BONAP county map]
Origin	Native	Native
Conservation status	Threatened in Washington (WANHP)	Not of concern
Sibling taxa	P. achoreum, P. austiniae, P. aviculare, P. californicum, P. douglasii, P. erectum, P. fowleri, P. majus, P. minimum, P. nuttallii, P. paronychia, P. polygaloides, P. ramosissimum, P. sawatchense, P. spergulariiforme	P. achoreum, P. austiniae, P. aviculare, P. californicum, P. douglasii, P. erectum, P. fowleri, P. majus, P. minimum, P. nuttallii, P. parryi, P. polygaloides, P. ramosissimum, P. sawatchense, P. spergulariiforme
Web links	Local floras: CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Polygonum parryi

Polygonum paronychia

Parry's knotweed, prickly knotweed

beach knotweed, black knotweed

Habit

Low, spreading shrub-like perennial here in Washington - typically less than 30 cm., though can get up to 100 cm. tall in some parts of its range.

Leaves

Alternate, simple, narrow, 1-2 cm long, with prominent midrib.

Flowers

Small pinkish or whitish, 5-6 mm long, with 5 parts; in small clusters along stem.

Fruits

Shiny black achenes 4-5 mm long.

Polygonum parryi

Polygonum paronychia

Identification notes

Can be separated from other Polygonum species by its perennial decumbent stems, lacerate hyaline stipules, axillary flower clusters, and coastal habitat.

Flowering time

June-July

April-September

Habitat

Vernal pools, seasonally damp ground at low elevations.

Coastal shorelines and sand dunes.

Distribution