Senecio vulgaris |
Senecio jacobaea |
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common groundsel, old-man-in-the-spring |
stinking willie, tansy ragwort |
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Habit | Herbs annual, (1)2–5(6+) dm; caudices taprooted. | Herbs perennial, 2–8(10) dm; caudices ± woody, branching, rhizomatous. |
Stems | usually 1, rarely 2–3, glabrous or sparsely and unevenly tomentose. |
1, or rarely 2–4 and loosely clustered, often purple-tinged, sparsely and unevenly tomentose. |
Leaves | evenly distributed along stems, oblanceolate to narrowly obovate or ovate, bases tapering; margins lobulate to dentate, ultimate margins secondarily denticulate; proximal petiolate; distal sessile. |
basal usually withering before flowering; cauline ± evenly distributed along stems; distal slightly smaller; ovate to broadly ovate, bases tapered, usually 1–3-pinnate, ultimate margins dentate; lobes obovate to spatulate, petiolate. |
Inflorescences | loose corymb-like arrays; bracts few, inconspicuous. |
compound corymb-like arrays; bracts conspicuous but small. |
Involucres | urceolate. |
widely cylindric or urn-shaped. |
Ray florets | 0. |
~13; rays 8–12 mm. |
Disc florets | (30)55–65. |
60–70+. |
Phyllaries | 21, 4–6 mm; tips usually black. |
13, 3–4(5); tips black or dark green. |
Calyculi | 2–4(6+) bractlets, 2–3 mm. |
2–6 bractlets, inconspicuous, usually < 2 mm. |
Fruits | 2–2.5 mm, sparsely to densely pubescent, rarely glabrous. |
0.75–1.3 mm, sparsely hairy or glabrous. |
Heads | 8–20. |
(10)20–60+. |
2n | =40. |
=40. |
Senecio vulgaris |
Senecio jacobaea |
|
Distribution | ||
Discussion | Disturbed areas. Flowering Feb–Oct. 0–1000 m. CR, ECas, Est, Lava, Sisk, WV. CA, ID, NV, WA; throughout North America; Asia, Europe. Exotic. |
Disturbed areas, pastures, roadsides. Flowering May–Sep. 0–1600 m. Casc, CR, Est, Sisk, WV. CA, ID, WA; north to British Columbia, northeast to MT, northeastern North America; Europe. Exotic. Senecio jacobea is an introduced weed, originally from Europe. It establishes in places with cool, wet summers and is particularly toxic to livestock. In most states where it occurs, this species has been declared a noxious weed. |
Source | Flora of Oregon, volume 2, page 342 Debra Trock |
Flora of Oregon, volume 2, page 340 Debra Trock |
Sibling taxa | ||
Synonyms | Jacobaea vulgaris | |
Web links |
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