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

dwarf mountain butterweed, dwarf mountain ragwort, Fremont's groundsel, Fremont's ragwort

Habit Perennials, (20–)50–120(–200) cm (caudices branched, ± woody). Perennials, 10–30(–40) cm (perennating bases subrhizomatous, spreading, sometimes knotty-woody).
Herbage

glabrous or sparsely floccose-tomentose when young.

(often purple-tinged) glabrous.

Stems

single or loosely clustered.

clustered (arching upward to semiprostrate).

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 or smaller and fewer distally (somewhat stiffish-succulent when fresh, proximalmost and distalmost often smaller, bractlike);

petiolate;

blades ovate or obovate to oblanceolate, 2–5(–7) × 1–3(–4) cm, bases ± truncate to tapered, margins laciniate to dentate or subentire.

Ray florets

± 8;

corolla laminae 9–15 mm.

± 8;

corolla laminae 8–12 mm.

Phyllaries

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

(± 8) ± 13 (± 21), 5–12 mm, tips green or brownish.

Calyculi

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

0 or of 1–5+ usually lance-deltate to linear, sometimes foliaceous, bractlets (lengths mostly 1/5–1/2 phyllaries).

Heads

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

1–5+.

Cypselae

glabrous.

glabrous or strigose-hirtellous, at least on angles.

2n

= 40, 80.

= 40, 40+, 80.

Senecio triangularis

Senecio fremontii

Phenology Flowering summer.
Habitat Damp places, open woodlands, especially rocky stream banks in coniferous forests
Elevation 100–3300 m [300–10800 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; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC
[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.)

Varieties 4 (4 in the flora).

The varieties are distinguished by morphologic tendencies plus their geographic ranges.

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

Key
1. Plants (10–)25–40 cm; stems straight or gently arching upward; leaves often to 7 × 3 cm, bases of larger ones weakly clasping; phyllaries (9–)10–12 mm
var. blitoides
1. Plants 10–20+ cm; stems usually arching upward; leaves usually smaller than 4 × 2 cm, bases not clasping; phyllaries 5–10 mm
→ 2
2. Leaf margins notably laciniate or laciniate-toothed (segments sometimes also toothed)
var. inexpectatus
2. Leaf margins toothed or subentire
→ 3
3. Leaves smaller and fewer distally; phyllaries 5–7(–8) mm
var. occidentalis
3. Leaves ± equally developed along stems; phyllaries (7–)8–10 mm
var. fremontii
Source FNA vol. 20, p. 566. Treatment author: Theodore M. Barkley†. FNA vol. 20, p. 564. Treatment author: Theodore M. Barkley†.
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. clarkianus, S. crassulus, S. elegans, S. elmeri, S. eremophilus, S. ertterae, S. erucifolius, S. flaccidus, 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
Subordinate taxa
S. fremontii var. blitoides, S. fremontii var. fremontii, S. fremontii var. inexpectatus, S. fremontii var. occidentalis
Synonyms S. gibbonsii, S. saliens, S. triangularis var. angustifolius S. ductoris
Name authority Hooker: Fl. Bor.-Amer. 1: 332, plate 115. (1834) Torrey & A. Gray: Fl. N. Amer. 2: 445. (1843)
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