Senecio triangularis |
Senecio squalidus |
|
---|---|---|
arrow-leaf groundsel, arrow-leaf ragwort, arrowleaf butterweed, groundsel |
oxford ragwort |
|
Habit | Perennials, (20–)50–120(–200) cm (caudices branched, ± woody). | Annuals (or perennials), 15–60+ cm (taprooted). |
Herbage | glabrous or sparsely floccose-tomentose when young. |
sparsely, unevenly floccose to subglabrous, glabrescent. |
Stems | single or loosely clustered. |
single (branching distally). |
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 (proximal, petioles ± winged); blades obovate to oblong, 4–10 × 2–4+ cm, mostly lyrate-pinnatifid to pinnate, bases tapered, ultimate margins dentate (distal leaves similar, smaller, sessile). |
Ray florets | ± 8; corolla laminae 9–15 mm. |
± 13; corolla laminae 5–8 mm. |
Phyllaries | (± 8) ± 13 (± 21), 6–10 mm, tips usually green, rarely black. |
(± 13) ± 21, 5–6+ mm, tips black. |
Calyculi | of 2–6 bractlets (rarely more than 2 mm). |
of 4–10+ bractlets (1–2+ mm). |
Heads | 10–30(–60) in corymbiform to subracemiform arrays. |
(3–)6–20 in open, cymiform arrays. |
Cypselae | glabrous. |
usually hairy. |
2n | = 40, 80. |
= 20. |
Senecio triangularis |
Senecio squalidus |
|
Phenology | Flowering summer. | Flowering late winter–spring or fall. |
Habitat | Damp places, open woodlands, especially rocky stream banks in coniferous forests | Disturbed sites (in regions of cool, damp climates) |
Elevation | 100–3300 m (300–10800 ft) | 0–300 m (0–1000 ft) |
Distribution |
AK; AZ; CA; CO; ID; MT; NM; NV; OR; WA; WY; AB; BC; NT; YT; PH
|
CA; NS; Europe [Introduced in North America] |
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 squalidus is native in Europe, where it is a common weed. It is apparently established in the San Francisco Bay area, California and has been reported from British Columbia, New Brunswick, and Nova Scotia. It is to be expected elsewhere. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 566. | FNA vol. 20, p. 560. |
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: 869. (1753) |
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