Flora of North America species comparison

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Senecio triangularis

Senecio cannabifolius

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

Aleutian ragwort
Habit Perennials, (20–)50–120(–200) cm (caudices branched, ± woody). Perennials, (50–)100–150+ cm (rhizomes fibrous-rooted).
Herbage

glabrous or sparsely floccose-tomentose when young.

unevenly tomentose, glabrescent, except persistently hairy on abaxial faces of leaves.
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 (basal and proximal withering before flowering); mostly petiolate (proximal);

blades oblong or ovate to oblong-lanceolate (pinnately or subpalmately parted, primary lobes 3–6+, lanceolate to lance-linear, 3–8+ cm), 10–20+ × 8–15+ cm, bases ± tapered, ultimate margins serrate (distal leaves similar, sessile, smaller).
Ray florets

± 8;

corolla laminae 9–15 mm.

± 5;

corolla laminae ca. 10 mm.
Phyllaries

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

± 13, 4–6 mm, tips green.
Calyculi

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

0 or of 1–5+ subulate bractlets (lengths about 1/3 phyllaries).
Heads

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

20–50 in corymbiform arrays.
Cypselae

glabrous.

glabrous.
2n

= 40, 80.

= 40.

Senecio triangularis

Senecio cannabifolius
Phenology Flowering summer. Flowering summer.
Habitat Damp places, open woodlands, especially rocky stream banks in coniferous forests Open meadows and slopes
Elevation 100–3300 m (300–10800 ft) 0–100 m (0–300 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
AK; Eurasia
[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 cannabifolius barely enters the flora from far-eastern Asia. Infraspecific taxa are recognized within S. cannabifolius in some floras of Asiatic regions; our plants are referable to var. cannabifolius.

Senecio cannabifolius has been treated in Jacobaea by E. Wiebe (2000); see discussion under 53. S. jacobaea.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 20, p. 566. FNA vol. 20, p. 569.
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. 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, S. wootonii
Synonyms S. gibbonsii, S. saliens, S. triangularis var. angustifolius Jacobaea cannabifolia, S. palmatus
Name authority Hooker: Fl. Bor.-Amer. 1: 332, plate 115. (1834) Lessing: Linnaea 6: 242. (1831)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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