Burke: Persicaria hydropiperoides vs. Persicaria lapathifolia

	Persicaria hydropiperoides	Persicaria lapathifolia
	water pepper, swamp smartweed	dock-leaf smartweed, pale smartweed, willow weed
Habit	Herbaceous perennial, up to 1 m. tall, usually decumbent and tending to root freely.	Somewhat pubescent annual with an erect, freely-branched stem 3-6 dm. tall.
Leaves	Leaves numerous on short petioles, alternate, scarcely reduced upward, lanceolate to oblong-lanceolate with an acute base, 5-12 cm. long; sheathing stipules 1-2 cm. long with bristly hairs around the top.	Leaf blades on short petioles, lanceolate to elliptic-lanceolate, 6-15 cm. long and about 3.5 cm. broad, covered with short, appressed to somewhat woolly hairs; stipules brownish, truncate with straight hairs around the top, but not lacerate, the tube not bristly.
Flowers	Inflorescence of 2 or more spike-like, interrupted racemes; perianth greenish to white or pinkish, 2.5-3 mm. long, 5-lobed half the length, the segments oblong and sub-equal; stamens 8 with short filaments	Inflorescence a loose panicle of several erect to pendant, many-flowered, spike-liked racemes, the branches glandular; perianth white or green to pink, the segments 4 or 5, the outer pair obovate, 2.5 mm. long, strongly 3-nerved.
Fruits	Achene with three sharp angles, black, smooth and shining, about 3 mm. long.

	Persicaria hydropiperoides	Persicaria lapathifolia
Identification notes		Achene lenticular, 2-3 mm. long, ovate, dark brown, smooth and shining.
Flowering time	July-September	May-September
Habitat	Moist to swampy areas, often growing in mud, from the lowlands to the lower mountain valleys.	Streambanks, pond and lakeshores and other wet places.
Distribution	Occurring chiefly west of the Cascades crest in Washington; British Columbia to Mexico and South America, east across North America to the Atlantic coast. [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	Native	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	P. amphibia, P. hydropiper, P. lapathifolia, P. maculosa, P. punctata, P. wallichii	P. amphibia, P. hydropiper, P. hydropiperoides, P. maculosa, P. punctata, P. 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 lapathifolia

water pepper, swamp smartweed

dock-leaf smartweed, pale smartweed, willow weed

Habit

Herbaceous perennial, up to 1 m. tall, usually decumbent and tending to root freely.

Somewhat pubescent annual with an erect, freely-branched stem 3-6 dm. tall.

Leaves

Leaves numerous on short petioles, alternate, scarcely reduced upward, lanceolate to oblong-lanceolate with an acute base, 5-12 cm. long; sheathing stipules 1-2 cm. long with bristly hairs around the top.

Leaf blades on short petioles, lanceolate to elliptic-lanceolate, 6-15 cm. long and about 3.5 cm. broad, covered with short, appressed to somewhat woolly hairs;

stipules brownish, truncate with straight hairs around the top, but not lacerate, the tube not bristly.

Flowers

Inflorescence of 2 or more spike-like, interrupted racemes;

perianth greenish to white or pinkish, 2.5-3 mm. long, 5-lobed half the length, the segments oblong and sub-equal;

stamens 8 with short filaments

Inflorescence a loose panicle of several erect to pendant, many-flowered, spike-liked racemes, the branches glandular;

perianth white or green to pink, the segments 4 or 5, the outer pair obovate, 2.5 mm. long, strongly 3-nerved.

Fruits

Achene with three sharp angles, black, smooth and shining, about 3 mm. long.

Persicaria hydropiperoides

Persicaria lapathifolia

Identification notes

Achene lenticular, 2-3 mm. long, ovate, dark brown, smooth and shining.

Flowering time

July-September

May-September

Habitat

Moist to swampy areas, often growing in mud, from the lowlands to the lower mountain valleys.

Streambanks, pond and lakeshores and other wet places.

Distribution

Occurring chiefly west of the Cascades crest in Washington; British Columbia to Mexico and South America, east across North America to the Atlantic coast.

[WildflowerSearch map]

[BONAP county map]