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arrow-leaf groundsel, arrow-leaf ragwort, arrowleaf butterweed, groundsel

Clark's ragwort

Habit Perennials, (20–)50–120(–200) cm (caudices branched, ± woody). Perennials, (50–)60–100(–120) cm (caudices fibrous-rooted).
Herbage

glabrous or sparsely floccose-tomentose when young.

sparsely floccose-tomentose, unevenly glabrescent.

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;

well-developed mid leaves: blades lanceolate to oblong,(8–)10–15(–18) × (2–)3–5(–9) cm overall, margins deeply dentate or irregularly pinnate-lobed to laciniate;

distal leaves sessile, weakly clasping.

Ray florets

± 8;

corolla laminae 9–15 mm.

± 8 or ± 13;

corolla laminae 8–12(–20) mm.

Phyllaries

(± 8) ± 13 (± 21), 6–10 mm, tips usually green, rarely black.

± 13 or ± 21, 5–8 mm, tips green.

Calyculi

of 2–6 bractlets (rarely more than 2 mm).

of 3–8+ linear to filiform bractlets (lengths 1/2–3/4+ phyllaries).

Heads

10–30(–60) in corymbiform to subracemiform arrays.

8–20 in corymbiform arrays.

Cypselae

glabrous.

glabrous.

2n

= 40, 80.

Senecio triangularis

Senecio clarkianus

Phenology Flowering summer. Flowering late summer.
Habitat Damp places, open woodlands, especially rocky stream banks in coniferous forests Moist meadows, conifer-dominated sites
Elevation 100–3300 m (300–10800 ft) 1400–2700 m (4600–8900 ft)
Distribution
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; OR; WA; WY; AB; BC; NT; YT; PH
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
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 clarkianus grows on west slopes of the central and southern Sierra Nevada.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 20, p. 566. FNA vol. 20, p. 566.
Parent taxa Asteraceae > tribe Senecioneae > Senecio Asteraceae > tribe Senecioneae > Senecio
Sibling taxa
S. actinella, S. amplectens, S. ampullaceus, S. aphanactis, S. arizonicus, S. aronicoides, S. astephanus, S. atratus, S. bigelovii, S. blochmaniae, S. californicus, S. cannabifolius, S. clarkianus, S. crassulus, S. elegans, S. elmeri, S. eremophilus, S. ertterae, S. erucifolius, S. flaccidus, S. fremontii, S. hydrophiloides, S. hydrophilus, S. integerrimus, S. jacobaea, S. lemmonii, S. lugens, S. lyonii, S. megacephalus, S. mohavensis, S. multidentatus, S. neowebsteri, S. parryi, S. pattersonensis, S. pseudoarnica, S. pudicus, S. quaylei, S. rapifolius, S. riddellii, S. sacramentanus, S. scorzonella, S. serra, S. sheldonensis, S. soldanella, S. spartioides, S. sphaerocephalus, S. spribillei, S. squalidus, S. sylvaticus, S. taraxacoides, S. viscosus, S. vulgaris, S. warnockii, S. wootonii
S. actinella, S. amplectens, S. ampullaceus, S. aphanactis, S. arizonicus, S. aronicoides, S. astephanus, S. atratus, S. bigelovii, S. blochmaniae, S. californicus, S. cannabifolius, S. crassulus, S. elegans, S. elmeri, S. eremophilus, S. ertterae, S. erucifolius, S. flaccidus, S. fremontii, S. hydrophiloides, S. hydrophilus, S. integerrimus, S. jacobaea, S. lemmonii, S. lugens, S. lyonii, S. megacephalus, S. mohavensis, S. multidentatus, S. neowebsteri, S. parryi, S. pattersonensis, S. pseudoarnica, S. pudicus, S. quaylei, S. rapifolius, S. riddellii, S. sacramentanus, S. scorzonella, S. serra, S. sheldonensis, S. soldanella, S. spartioides, S. sphaerocephalus, S. spribillei, S. squalidus, S. sylvaticus, S. taraxacoides, S. triangularis, S. viscosus, S. vulgaris, S. warnockii, S. wootonii
Synonyms S. gibbonsii, S. saliens, S. triangularis var. angustifolius
Name authority Hooker: Fl. Bor.-Amer. 1: 332, plate 115. (1834) A. Gray: Proc. Amer. Acad. Arts 7: 362. (1868)
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