Senecio jacobaea |
Senecio sacramentanus |
|
---|---|---|
stinking willie, tansy ragwort |
Sacramento ragwort |
|
Habit | Perennials, 20–80(–100) cm (taprooted or branched caudices surmounting taproots). | Perennials, 20–50 cm (caudices fibrous-rooted). |
Herbage | sparsely and unevenly tomentose, glabrescent except in leaf axils and among heads. |
sparsely pubescent to tomentose (especially on abaxial leaf faces and among heads). |
Stems | (often purplish-tinged) usually single, sometimes loosely clustered. |
single or loosely clustered. |
Leaves | ± evenly distributed (basal often withering before flowering); petiolate (sometimes obscurely); blades ovate to broadly ovate (usually 1–3-pinnate, lobes mostly obovate to spatulate), (4–)7–20(–30) × (1–)2–5(–12) cm, bases usually tapered, ultimate margins dentate (distal leaves similar, smaller). |
progressively reduced distally; petiolate; blades triangular, triangular-lanceolate, or lanceolate, 3–10(–15) × 1.5–4 cm, bases cordate to truncate or tapered, margins serrate or dentate (mid and distal leaves sessile, bractlike). |
Ray florets | ± 13; corolla laminae 8–12 mm. |
0. |
Phyllaries | ± 13, 3–4(–5) mm, tips black or greenish. |
± 8, 6–9 mm, tips green. |
Calyculi | of 2–6 (inconspicuous) bractlets (less than 2 mm). |
of 2–5+ lance-deltate to filiform bractlets (lengths 1/5–1/2 phyllaries). |
Heads | (10–)20–60+ in corymbiform arrays. |
nodding, 6–10+ in racemiform-paniculiform arrays. |
Cypselae | all sparsely hairy or ray cypselae glabrous. |
glabrous. |
2n | = 40. |
|
Senecio jacobaea |
Senecio sacramentanus |
|
Phenology | Flowering spring–early summer(–fall). | Late summer. |
Habitat | Disturbed sites, pastures, roadsides, and waste grounds | Montane meadows |
Elevation | 0–1500 m (0–4900 ft) | 3000–3500 m (9800–11500 ft) |
Distribution |
CA; ID; IL; MA; ME; MI; MT; NJ; NY; OR; PA; WA; BC; NB; NF; NS; ON; PE; QC; SPM; Europe [Introduced in North America]
|
NM |
Discussion | Senecio jacobaea is a weed introduced from Europe and now well established in places of cool, damp summers. It is toxic to livestock and legally noxious in most states and provinces where it occurs. The Russian botanist E. Wiebe (2000) resuscitated Jacobaea for plants that are treated here as Senecio jacobaea, S. erucifolius, and S. cannabifolius. Phylogenetic studies may confirm the utility of recognizing Jacobaea as a distinct genus; to do so here would be premature. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 20, p. 568. | FNA vol. 20, p. 550. |
Parent taxa | Asteraceae > tribe Senecioneae > Senecio | Asteraceae > tribe Senecioneae > Senecio |
Sibling taxa | ||
Synonyms | Jacobaea vulgaris | |
Name authority | Linnaeus: Sp. Pl. 2: 870. (1753) | Wooton & Standley: Contr. U.S. Natl. Herb. 16: 194. (1913) |
Web links |
|