Burke: Polygonum polygaloides vs. Polygonum spergulariiforme

	Polygonum polygaloides	Polygonum spergulariiforme
		fall knotweed, spurry knotweed
Habit	Glabrous, erect or ascending, usually freely branched annual 6-20 cm. tall.	Erect to rounded annual, the stems simple or freely-branched, up to 5 dm. tall, the branches wiry, sharply angled above.
Leaves	Linear, 10-25 mm. long, 1-2 mm. broad, basally jointed; stipules lacerate, 4-8 mm. long.	Leaves alternate, basally jointed, linear to narrowly oblong-oblanceolate, 1-3 cm. long and 1-2 mm. wide; stipules sheathing, lacerate, 3-6 mm. long.
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 1-4 in the axils of the upper leaves and crowded, leaf-like bracts which exceed the flowers; pedicles slender, 1-2 mm. long; the 5 perianth segments 3-4 mm. long, attached 1/3 their length, pinkish with a green midrib; stamens 8; styles 3, 0.5 mm. long.
Fruits	Achene with three sharp angles, dark brown, dull, longitudinally striate, 2 mm. long.	Achene 3-angled, 3-4 mm. long, black, shining and smooth.

	Polygonum polygaloides	Polygonum spergulariiforme
Flowering time	June-August	June-September
Habitat	Meadows, vernal pools and rocky ridges, lowlands to mid-elevations in the mountains.	Balds, prairies, and headlands in gravelly, sandy or heavy, dry or moist soil at low elevations.
Distribution	Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains. [WildflowerSearch map] [BONAP county map]	Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California, east to Idaho, Montana, and Wyoming. [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. majus, P. minimum, P. nuttallii, P. paronychia, P. parryi, P. polygaloides, P. ramosissimum, P. sawatchense
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 spergulariiforme

fall knotweed, spurry knotweed

Habit

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

Erect to rounded annual, the stems simple or freely-branched, up to 5 dm. tall, the branches wiry, sharply angled above.

Leaves

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

stipules lacerate, 4-8 mm. long.

Leaves alternate, basally jointed, linear to narrowly oblong-oblanceolate, 1-3 cm. long and 1-2 mm. wide;

stipules sheathing, lacerate, 3-6 mm. long.

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 1-4 in the axils of the upper leaves and crowded, leaf-like bracts which exceed the flowers; pedicles slender, 1-2 mm. long; the 5 perianth segments 3-4 mm. long, attached 1/3 their length, pinkish with a green midrib;

stamens 8;

styles 3, 0.5 mm. long.

Fruits

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

Achene 3-angled, 3-4 mm. long, black, shining and smooth.

Polygonum polygaloides

Polygonum spergulariiforme

Flowering time

June-August

June-September

Habitat

Meadows, vernal pools and rocky ridges, lowlands to mid-elevations in the mountains.

Balds, prairies, and headlands in gravelly, sandy or heavy, dry or moist soil at low elevations.

Distribution

Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.

[WildflowerSearch map]

[BONAP county map]

Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California, east to Idaho, Montana, and Wyoming.

[WildflowerSearch map]

[BONAP county map]

Origin

Native

Conservation status

Not of concern

Sibling taxa