Burke: Senecio integerrimus vs. Senecio sylvaticus

	Senecio integerrimus	Senecio sylvaticus
	one-stemmed butterweed, western groundsel	wood groundsel, woodland groundsel, woodland ragwort
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.	Sparsely pubescent, tap-rooted annual, usually with a simple stem 1.5-8 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 more or less pinnatifid and irregularly toothed, 2-12 cm. long and 4-40 mm. wide, narrowly lanceolate in outline.
Flowers	Heads several to numerous in a rather congested inflorescence; involucre 5-10 mm. long; rays 6-15 mm. long, usually yellow, occasionally cream.

	Senecio integerrimus	Senecio sylvaticus
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. vulgaris are black-tipped) and the aroma (only S. sylvaticus is malodorous).
Flowering time	May-August	May-September
Habitat	Meadows and seasonally moist open areas from low elevations to the subalpine.	Roadsides, fields, forest edge, wastelots, and other disturbed areas at low elevation.
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 chiefly west of the Cascades crest in Washington; British Columbia to California, also in eastern North America. [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. triangularis, S. viscosus, S. vulgaris
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 WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Senecio sylvaticus

one-stemmed butterweed, western groundsel

wood groundsel, woodland groundsel, woodland ragwort

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.

Sparsely pubescent, tap-rooted annual, usually with a simple stem 1.5-8 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 more or less pinnatifid and irregularly toothed, 2-12 cm. long and 4-40 mm. wide, narrowly lanceolate in outline.

Flowers

Heads several to numerous in a rather congested inflorescence;

involucre 5-10 mm. long;

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

Senecio sylvaticus

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. vulgaris are black-tipped) and the aroma (only S. sylvaticus is malodorous).

Flowering time

May-August

May-September

Habitat

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

Roadsides, fields, forest edge, wastelots, and other disturbed areas at low elevation.

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]