The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

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

Wooton's butterweed, Wooton's ragwort

Habit Perennials, (20–)50–120(–200) cm (caudices branched, ± woody). Perennials, (15–)20–45(–60) cm (caudices erect or weakly spreading).
Herbage

glabrous or sparsely floccose-tomentose when young.

nearly always glaucous, glabrous.

Stems

single or loosely clustered.

single or clustered.

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).

(thickish and turgid) progressively reduced distally; petiolate;

blades ovate or obovate to lanceolate, 4–9(–15+) × 1.5–3(–4+) cm, bases tapered, margins wavy or subentire (often with callous denticles; mid and distal leaves sessile, bractlike).

Ray florets

± 8;

corolla laminae 9–15 mm.

8–10;

corolla laminae 4–10 mm.

Phyllaries

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

± 13 (± 21), 6–9 mm, tips green to brownish (not blackened).

Calyculi

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

of 1–3+ oblong to lance-linear bractlets (less than 3 mm).

Heads

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

(3–)8–24+ in corymbiform arrays.

Cypselae

glabrous.

glabrous.

2n

= 40, 80.

= 40.

Senecio triangularis

Senecio wootonii

Phenology Flowering summer. Flowering spring–summer.
Habitat Damp places, open woodlands, especially rocky stream banks in coniferous forests Damp or drying sites, often in rocky, moderately disturbed sites
Elevation 100–3300 m (300–10800 ft) 2000–3500 m (6600–11500 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
AZ; CO; NM; TX; Mexico
[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 wootonii reaches its southern limit in Coahuila and Chihuahua, Mexico; farther south, it is replaced by S. toluccanus de Candolle, a similar, larger, more robust species.

(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
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. 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
Synonyms S. gibbonsii, S. saliens, S. triangularis var. angustifolius S. anacletus
Name authority Hooker: Fl. Bor.-Amer. 1: 332, plate 115. (1834) Greene: Bull. Torrey Bot. Club 25: 122, plate 331, figs. 1, 2. (1898)
Web links