Senecio sylvaticus |
Senecio hydrophilus |
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heath groundsel, wood groundsel, woodland groundsel, woodland ragwort |
alkali marsh groundsel, alkali-marsh butterweed, alkali-marsh ragwort, water groundsel, water ragwort |
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Habit | Annuals, (15–)30–80+ cm (taproots fibrous-rooted). | Perennials (biennials?), 40–100(–200) cm (caudices foreshortened, roots fleshy-fibrous). |
Herbage | puberulent (hairs abundant, curly). |
(often sea-green, usually glaucous) glabrous. |
Stems | single. |
single or 2–4 loosely clustered. |
Leaves | evenly distributed; petiolate; blades obovate to oblong, 3–7(–12) × 1–3(–4) cm, usually 1–2-pinnate, bases tapered, ultimate margins dentate (distal leaves similar, clasping, bractlike). |
progressively reduced distally; ± petiolate; blades elliptic to oblanceolate, 5–20+ × (1–)2–10 cm, bases tapered, margins denticulate or entire (mid and distal leaves sessile, bractlike). |
Ray florets | 0 or 1–8+; corolla laminae usually 1–2+ mm (barely surpassing phyllaries). |
(0) ca. 5; corolla laminae 3–5 mm. |
Phyllaries | ± 13 (± 21), 4–7+ mm, tips greenish or minutely black. |
± 8 or ± 13, 5–8 mm, tips frequently black. |
Calyculi | 0 or of 1–5+ linear to filiform bractlets. |
of 2–4+ bractlets (less than 2 mm). |
Heads | 12–24 in corymbiform arrays. |
20–40(–80+) in compound corymbiform arrays. |
Cypselae | hairy (especially on angles). |
glabrous. |
2n | = 40. |
= 40. |
Senecio sylvaticus |
Senecio hydrophilus |
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Phenology | Flowering late spring–summer (northern areas of cool, climate); winter (southern areas). | Flowering spring–early summer. |
Habitat | Mildly disturbed woodlands, open, sandy sites | Marshes, swampy places, standing water, alkaline sites |
Elevation | 100–300 m (300–1000 ft) | (0–)200–2500 m ((0–)700–8200 ft) |
Distribution |
CA; LA; MA; MI; NJ; OH; OR; PA; WA; WI; BC; NB; NF; NS; PE; QC; Eurasia [Introduced in North America]
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CA; CO; ID; MT; NV; OR; SD; UT; WA; WY; BC
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Discussion | Senecio sylvaticus is a Eurasian weed that favors cool, wet climates. It is well established in coastal areas of the Pacific Coast and in parts of Newfoundland and Quebec; elsewhere in the flora, it appears to be sporadic. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 20, p. 563. | FNA vol. 20, p. 557. |
Parent taxa | Asteraceae > tribe Senecioneae > Senecio | Asteraceae > tribe Senecioneae > Senecio |
Sibling taxa | ||
Synonyms | S. hydrophilus var. pacificus | |
Name authority | Linnaeus: Sp. Pl. 2: 868. (1753) | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 411. (1841) |
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