Burke: Senecio integerrimus vs. Senecio vulgaris

	Senecio integerrimus	Senecio vulgaris
	one-stemmed butterweed, western groundsel	common groundsel, old man in the spring
Habit	Stout, fibrous-rooted perennial from a very short crown; stems solitary, 2-7 dm. tall; plants covered with white, loose hairs when young, but these missing in older plants except in the leaf axils.	Simple or strongly-branched, tap-rooted annual, 1-4 dm. tall.
Leaves	Usually entire, elliptic to broadly lanceolate, the basal ones petiolate, the blade and petiole 6-25 cm. long and 1-6 cm wide; cauline leaves progressively reduced upward, becoming sessile toward the top of the stem.	Leafy throughout, the leaves coarsely and irregularly toothed to pinnatifid, 2-10 cm. long and 5-45 mm. wide, the lower tapering to a petiole, the upper sessile and clasping.
Flowers	Heads several to numerous in a rather congested inflorescence; involucre 5-10 mm. long; rays 6-15 mm. long, usually yellow, occasionally cream.	Heads many, strictly rayless, the flowers all tubular and perfect; disk usually 5-10 mm. wide; involucre 5-8 mm. high, the princeple bracts about 21, the bracteoles short but well-developed, black tipped; pappus copious.

	Senecio integerrimus	Senecio vulgaris
Identification notes	A Senecio growing on dry ground, with a fairly tall, single, upright stem and large, entire leaves is probably this species, especially if the leaves are lightly covered with white, tangled hairs.	Separate from the only other annual Senecio in our area by the number of involucre bracts (S. vulgaris has about 21, S. sylvaticus,13), the bracteoles (only S. vulgarisÃ† are black-tipped) and the aroma (only S. sylvaticus is malodorous).
Flowering time	May-August	February-September
Habitat	Meadows and seasonally moist open areas from low elevations to the subalpine.	Roadsides, waste ground, lawns, and other disturbed, open sites.
Distribution	Occurring chiefly east of the Cascades crest in Washington, where widely distributed; British Columbia to California, east to the Great Plains and Great Lakes region. [WildflowerSearch map] [BONAP county map]	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]
Origin	Native	Introduced from Europe
Conservation status	Not of concern	Not of concern
Sibling taxa	S. elmeri, S. fremontii, S. hydrophiloides, S. hydrophilus, S. lugens, S. neowebsteri, S. serra, S. sylvaticus, S. triangularis, S. viscosus, S. vulgaris	S. elmeri, S. fremontii, S. hydrophiloides, S. hydrophilus, S. integerrimus, S. lugens, S. neowebsteri, S. serra, S. sylvaticus, S. triangularis, S. viscosus
Subordinate taxa	S. integerrimus var. exaltatus, S. integerrimus var. ochroleucus
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, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Senecio vulgaris

one-stemmed butterweed, western groundsel

common groundsel, old man in the spring

Habit

Stout, fibrous-rooted perennial from a very short crown; stems solitary, 2-7 dm. tall; plants covered with white, loose hairs when young, but these missing in older plants except in the leaf axils.

Simple or strongly-branched, tap-rooted annual, 1-4 dm. tall.

Leaves

Usually entire, elliptic to broadly lanceolate, the basal ones petiolate, the blade and petiole 6-25 cm. long and 1-6 cm wide;

cauline leaves progressively reduced upward, becoming sessile toward the top of the stem.

Leafy throughout, the leaves coarsely and irregularly toothed to pinnatifid, 2-10 cm. long and 5-45 mm. wide, the lower tapering to a petiole, the upper sessile and clasping.

Flowers

Heads several to numerous in a rather congested inflorescence;

involucre 5-10 mm. long;

rays 6-15 mm. long, usually yellow, occasionally cream.

Heads many, strictly rayless, the flowers all tubular and perfect; disk usually 5-10 mm. wide;

involucre 5-8 mm. high, the princeple bracts about 21, the bracteoles short but well-developed, black tipped;

pappus copious.

Senecio vulgaris

Identification notes

A Senecio growing on dry ground, with a fairly tall, single, upright stem and large, entire leaves is probably this species, especially if the leaves are lightly covered with white, tangled hairs.

Separate from the only other annual Senecio in our area by the number of involucre bracts (S. vulgaris has about 21, S. sylvaticus,13), the bracteoles (only S. vulgarisÃ† are black-tipped) and the aroma (only S. sylvaticus is malodorous).

Flowering time

May-August

February-September

Habitat

Meadows and seasonally moist open areas from low elevations to the subalpine.

Roadsides, waste ground, lawns, and other disturbed, open sites.

Distribution

Occurring chiefly east of the Cascades crest in Washington, where widely distributed; British Columbia to California, east to the Great Plains and Great Lakes region.

[WildflowerSearch map]

[BONAP county map]