Burke: Persicaria wallichii vs. Persicaria maculosa

	Persicaria wallichii	Persicaria maculosa
	garden knotweed, Himalayan knotweed	heartweed, lady's-thumb, spotted lady's-thumb, redshank
Habit	Vigorous, rhizomatous perennial with numerous, erect, reddish-brown, leafy, branching stems 1.5-2 m. tall.	Usually a glabrous annual, simple to branched, erect to spreading, up to 1 m. tall.
Leaves	Leaves alternate, the lower petiolate, becoming subsessile upward; leaf blade oblong-lanceolate to ovate-lanceolate, acuminate, up to 20 cm. long, the base truncate to cordate; stipules sheathing, not lacerate.	Leaf blades elliptic-lanceolate to narrowly oblong-lanceolate, 5-10 cm. long, usually with a purplish triangular or lunar spot about mid-length, narrowed to a short, thick, non-jointed petiole; stipules obliquely cylindric-conic, never lacerate, bristly along the nerves.
Flowers	Inflorescence an open, terminal panicle; flowers white, perfect; the 5 perianth segments obovate, 3-4 mm. long, not keeled.	Inflorescence of crowded, pedunculate, compound racemes; flowers white, usually strongly pinkish-tinged; perianth 1.5-2 mm. long, 5-parted.

	Persicaria wallichii	Persicaria maculosa
Identification notes	Achene 3-angled, black, smooth and shining, 3 mm. long.	Achene lenticular, 2-2.5 mm. long, ovate-rotund in outline, black, smooth and shining.
Flowering time	July-October	March-September
Habitat	Waste areas, roadsides, and other disturbed areas where often where somewhat moist.	A weedy species, usually on moist, cultivated or otherwise disturbed soil.
Distribution	Occurring west of the Cascades crest in Washington; British Columbia to California; also in eastern North America. [WildflowerSearch map] [BONAP county map]	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]
Origin	Introduced from eastern Asia	Introduced from Eurasia
Conservation status	Not of concern	Not of concern
Sibling taxa	P. amphibia, P. hydropiper, P. hydropiperoides, P. lapathifolia, P. maculosa, P. punctata	P. amphibia, P. hydropiper, P. hydropiperoides, P. lapathifolia, P. punctata, P. wallichii
Subordinate taxa	P. wallichii var. wallichii
Web links	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	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

Persicaria wallichii

Persicaria maculosa

garden knotweed, Himalayan knotweed

heartweed, lady's-thumb, spotted lady's-thumb, redshank

Habit

Vigorous, rhizomatous perennial with numerous, erect, reddish-brown, leafy, branching stems 1.5-2 m. tall.

Usually a glabrous annual, simple to branched, erect to spreading, up to 1 m. tall.

Leaves

Leaves alternate, the lower petiolate, becoming subsessile upward;

leaf blade oblong-lanceolate to ovate-lanceolate, acuminate, up to 20 cm. long, the base truncate to cordate;

stipules sheathing, not lacerate.

Leaf blades elliptic-lanceolate to narrowly oblong-lanceolate, 5-10 cm. long, usually with a purplish triangular or lunar spot about mid-length, narrowed to a short, thick, non-jointed petiole;

stipules obliquely cylindric-conic, never lacerate, bristly along the nerves.

Flowers

Inflorescence an open, terminal panicle;

flowers white, perfect; the 5 perianth segments obovate, 3-4 mm. long, not keeled.

Inflorescence of crowded, pedunculate, compound racemes;

flowers white, usually strongly pinkish-tinged;

perianth 1.5-2 mm. long, 5-parted.