Burke: Polygonum parryi vs. Polygonum majus

	Polygonum parryi	Polygonum majus
	Parry's knotweed, prickly knotweed	Palouse knotweed, wiry knotweed
Habit		Erect annual, the stem strongly angled, simple or freely-branched, 1-3 dm. tall.
Leaves		Leaves alternate, numerous, gradually reduced upward, the lower leaves linear to oblong, sessile, 2-5 cm. long and 2-7 mm. wide, jointed at the base; stipules 10-15 mm. long, lacerate.
Flowers		Flowers mostly paired in open elongate racemes, in the axils of reduced bracts or the lowest in leaf axils, the pedicles slender, reflexed; the 5 perianth segments 4-5 mm. long, attached 1/5 their length, with a greenish midvein and white to pink margins, obtuse; stamens 8, anthers purple; styles 3, short.

	Polygonum parryi	Polygonum majus
Identification notes		Achene 3-angled, 3.5-4 mm. long and Â½ as wide, smooth, black and shining, tapered at each end.
Flowering time	June-July	May-August
Habitat	Vernal pools, seasonally damp ground at low elevations.	Dry, often semi-barren, gravelly to heavy soil, sagebrush desert to lower mountains.
Distribution	Occurring in the east end of the Columbia River Gorge in Washington; south-central Washington to California. [WildflowerSearch map] [BONAP county map]	Occurring east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains. [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. minimum, P. nuttallii, P. paronychia, 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 WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Polygonum majus

Parry's knotweed, prickly knotweed

Palouse knotweed, wiry knotweed

Habit

Erect annual, the stem strongly angled, simple or freely-branched, 1-3 dm. tall.

Leaves

Leaves alternate, numerous, gradually reduced upward, the lower leaves linear to oblong, sessile, 2-5 cm. long and 2-7 mm. wide, jointed at the base;

stipules 10-15 mm. long, lacerate.

Flowers

Flowers mostly paired in open elongate racemes, in the axils of reduced bracts or the lowest in leaf axils, the pedicles slender, reflexed; the 5 perianth segments 4-5 mm. long, attached 1/5 their length, with a greenish midvein and white to pink margins, obtuse;

stamens 8, anthers purple;

styles 3, short.