Senecio triangularis |
Senecio sylvaticus |
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arrow-leaf groundsel, arrow-leaf ragwort, arrowleaf butterweed, groundsel |
heath groundsel, wood groundsel, woodland groundsel, woodland ragwort |
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Habit | Perennials, (20–)50–120(–200) cm (caudices branched, ± woody). | Annuals, (15–)30–80+ cm (taproots fibrous-rooted). |
Herbage | glabrous or sparsely floccose-tomentose when young. |
puberulent (hairs abundant, curly). |
Stems | single or loosely clustered. |
single. |
Leaves | evenly distributed; petiolate; blades narrowly triangular, (3–)4–10+ × 2–6 cm, bases usually ± truncate, sometimes tapered, margins usually dentate, rarely subentire (distal leaves subsessile, smaller). |
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). |
Ray florets | ± 8; corolla laminae 9–15 mm. |
0 or 1–8+; corolla laminae usually 1–2+ mm (barely surpassing phyllaries). |
Phyllaries | (± 8) ± 13 (± 21), 6–10 mm, tips usually green, rarely black. |
± 13 (± 21), 4–7+ mm, tips greenish or minutely black. |
Calyculi | of 2–6 bractlets (rarely more than 2 mm). |
0 or of 1–5+ linear to filiform bractlets. |
Heads | 10–30(–60) in corymbiform to subracemiform arrays. |
12–24 in corymbiform arrays. |
Cypselae | glabrous. |
hairy (especially on angles). |
2n | = 40, 80. |
= 40. |
Senecio triangularis |
Senecio sylvaticus |
|
Phenology | Flowering summer. | Flowering late spring–summer (northern areas of cool, climate); winter (southern areas). |
Habitat | Damp places, open woodlands, especially rocky stream banks in coniferous forests | Mildly disturbed woodlands, open, sandy sites |
Elevation | 100–3300 m (300–10800 ft) | 100–300 m (300–1000 ft) |
Distribution |
AK; AZ; CA; CO; ID; MT; NM; NV; OR; WA; WY; AB; BC; NT; YT; PH
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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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Discussion | Plants of Senecio triangularis with narrow, subentire leaves that taper to the petioles are occasionally encountered in acid bogs in Oregon and Washington and less frequently elsewhere. They are regarded as edaphic variants; they have been recognized as var. angustifolius. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 20, p. 566. | FNA vol. 20, p. 563. |
Parent taxa | Asteraceae > tribe Senecioneae > Senecio | Asteraceae > tribe Senecioneae > Senecio |
Sibling taxa | ||
Synonyms | S. gibbonsii, S. saliens, S. triangularis var. angustifolius | |
Name authority | Hooker: Fl. Bor.-Amer. 1: 332, plate 115. (1834) | Linnaeus: Sp. Pl. 2: 868. (1753) |
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