Senecio triangularis |
Senecio atratus |
|
---|---|---|
arrow-leaf groundsel, arrow-leaf ragwort, arrowleaf butterweed, groundsel |
tall blacktip ragwort |
|
Habit | Perennials, (20–)50–120(–200) cm (caudices branched, ± woody). | Perennials, (20–)35–70(–80+) cm (rhizomes or caudices branched, erect to weakly creeping). |
Herbage | glabrous or sparsely floccose-tomentose when young. |
floccose-tomentose to canescent, sometimes unevenly glabrescent. |
Stems | single or loosely clustered. |
1–(2–5). |
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). |
progressively reduced distally; petiolate; blades oblong-ovate to oblanceolate, (5–)10–30 × 1.5–4(–6) cm, bases tapered, margins dentate (denticles, dark, callous; mid leaves similar, sessile, smaller; distal leaves bractlike). |
Ray florets | ± 8; corolla laminae 9–15 mm. |
(± 3) ± 5; corolla laminae 5–8 mm. |
Phyllaries | (± 8) ± 13 (± 21), 6–10 mm, tips usually green, rarely black. |
(± 5) ± 8, 6–8 mm, tips black. |
Calyculi | of 2–6 bractlets (rarely more than 2 mm). |
of 2–5 linear bractlets (lengths to 1/3 phyllaries). |
Heads | 10–30(–60) in corymbiform to subracemiform arrays. |
20–60+ in corymbiform or subpaniculiform arrays. |
Cypselae | glabrous. |
glabrous. |
2n | = 40, 80. |
= 40. (A report of 2n = 46 is presumably erroneous.) |
Senecio triangularis |
Senecio atratus |
|
Phenology | Flowering summer. | Flowering late spring–early fall. |
Habitat | Damp places, open woodlands, especially rocky stream banks in coniferous forests | Dry or drying, rocky or sandy sites in coniferous areas, especially sites with frequent disturbance |
Elevation | 100–3300 m (300–10800 ft) | 2800–4000 m (9200–13100 ft) |
Distribution |
AK; AZ; CA; CO; ID; MT; NM; NV; OR; WA; WY; AB; BC; NT; YT; PH
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CO; NM; UT; WY
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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.) |
|
Source | FNA vol. 20, p. 566. | FNA vol. 20, p. 554. |
Parent taxa | Asteraceae > tribe Senecioneae > Senecio | Asteraceae > tribe Senecioneae > Senecio |
Sibling taxa | ||
Synonyms | S. gibbonsii, S. saliens, S. triangularis var. angustifolius | S. atratus var. milleflorus, S. milleflorus |
Name authority | Hooker: Fl. Bor.-Amer. 1: 332, plate 115. (1834) | Greene: Pittonia 3: 105. (1896) |
Web links |