Burke: Polygonum polygaloides vs. Polygonum majus

	Polygonum polygaloides	Polygonum majus
		Palouse knotweed, wiry knotweed
Habit	Glabrous, erect or ascending, usually freely branched annual 6-20 cm. tall.	Erect annual, the stem strongly angled, simple or freely-branched, 1-3 dm. tall.
Leaves	Linear, 10-25 mm. long, 1-2 mm. broad, basally jointed; stipules lacerate, 4-8 mm. long.	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	Crowded in groups of 1-4 on the branch tips, the branches arising from the axils of obovate, prominent, strongly white-margined bracts that have a green mid-rib; perianth 2.5 mm. long, divided over half the length, the 5 segments oblong-lanceolate, with greenish center and prominent white to pink margins.	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.
Fruits	Achene with three sharp angles, dark brown, dull, longitudinally striate, 2 mm. long.

	Polygonum polygaloides	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-August	May-August
Habitat	Meadows, vernal pools and rocky ridges, lowlands to mid-elevations in the mountains.	Dry, often semi-barren, gravelly to heavy soil, sagebrush desert to lower mountains.
Distribution	Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains. [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	Not of concern	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. parryi, 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
Subordinate taxa	P. polygaloides ssp. confertiflorum, P. polygaloides ssp. kelloggii, P. polygaloides ssp. polygaloides
Web links	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	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

Palouse knotweed, wiry knotweed

Habit

Glabrous, erect or ascending, usually freely branched annual 6-20 cm. tall.

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

Leaves

Linear, 10-25 mm. long, 1-2 mm. broad, basally jointed;

stipules lacerate, 4-8 mm. long.

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

Crowded in groups of 1-4 on the branch tips, the branches arising from the axils of obovate, prominent, strongly white-margined bracts that have a green mid-rib;

perianth 2.5 mm. long, divided over half the length, the 5 segments oblong-lanceolate, with greenish center and prominent white to pink margins.

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.

Fruits

Achene with three sharp angles, dark brown, dull, longitudinally striate, 2 mm. long.