Burke: Sonchus oleraceus

	Sonchus oleraceus
	common sow-thistle
Habit	Mostly glabrous annual with a short taproot, 1-10 dm. tall, the juice milky.
Leaves	Lowermost leaves ovate and petiolate, the others pinnatifid, with backward-pointing segments, or occasionally merely toothed, 6-30 cm. long and 1-15 cm. wide, the margins weakly prickly; all leaves with prominent, pointed auricles; leaves progressively less-divided upwards and somewhat reduced.
Flowers	Heads several in a flat-topped inflorescence, relatively small, usually only 1.5-2.5 cm. wide; involucre 9-14 mm. high, the bracts of uneven lengths, some quite short; corollas all ligulate and perfect, yellow; pappus of numerous, white, capillary bristles.
Fruits	Achenes 2.5-3 mm. long, with transverse wrinkles.

	Sonchus oleraceus
Flowering time	June-October
Habitat	Forest edge, balds, prairies, roadsides, ditches, wastelots, and other disturbed open areas at low elevations.
Distribution	Occurring on both sides of the Cascades crest in Washington, but more common west of the crest; Alaska to California, east across North America to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]
Origin	Introduced from Europe
Conservation status	Not of concern
Sibling taxa	S. arvensis, S. asper
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

Sonchus oleraceus

common sow-thistle

Habit

Mostly glabrous annual with a short taproot, 1-10 dm. tall, the juice milky.

Leaves

Lowermost leaves ovate and petiolate, the others pinnatifid, with backward-pointing segments, or occasionally merely toothed, 6-30 cm. long and 1-15 cm. wide, the margins weakly prickly; all leaves with prominent, pointed auricles;

leaves progressively less-divided upwards and somewhat reduced.

Flowers

Heads several in a flat-topped inflorescence, relatively small, usually only 1.5-2.5 cm. wide;

involucre 9-14 mm. high, the bracts of uneven lengths, some quite short;

corollas all ligulate and perfect, yellow;

pappus of numerous, white, capillary bristles.

Fruits

Achenes 2.5-3 mm. long, with transverse wrinkles.

Sonchus oleraceus

Flowering time

June-October

Habitat

Forest edge, balds, prairies, roadsides, ditches, wastelots, and other disturbed open areas at low elevations.

Distribution

Occurring on both sides of the Cascades crest in Washington, but more common west of the crest; Alaska to California, east across North America to the Atlantic Coast.

[WildflowerSearch map]

[BONAP county map]

Origin

Introduced from Europe

Conservation status

Not of concern

Sibling taxa

S. arvensis, S. asper

Web links