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

Warnock's ragwort

Habit Perennials, (20–)50–120(–200) cm (caudices branched, ± woody). Subshrubs, 20–40 cm (taproots forming woody crowns).
Herbage

glabrous or sparsely floccose-tomentose when young.

closely, unevenly lanate-floccose, glabrescent.

Stems

single or loosely clustered.

usually multiple (strict or nearly so, arching-erect).

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).

(often recurved and thickish-turgid) concentrated distally on stems;

sessile or obscurely petiolate;

blades narrowly linear to filiform (2–7 cm × 1 mm), bases ± linear, margins entire.

Ray florets

± 8;

corolla laminae 9–15 mm.

usually ± 8, rarely 0;

corolla laminae 5–10 mm.

Phyllaries

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

± 13, 5–8 mm, tips green or minutely black.

Calyculi

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

0 or of 3–5 bractlets (lengths less than 1/2 phyllaries).

Heads

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

3–10 in corymbiform arrays (involucres weakly campanulate).

Cypselae

glabrous.

glabrous.

2n

= 40, 80.

Senecio triangularis

Senecio warnockii

Phenology Flowering summer. Flowering fall (perhaps spring–summer).
Habitat Damp places, open woodlands, especially rocky stream banks in coniferous forests Open sites, gypseous soils
Elevation 100–3300 m (300–10800 ft) 800–1500 m (2600–4900 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
NM; TX
[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.)

Of conservation concern.

Senecio warnockii is infrequently collected; additional study may show it to be an edaphic phase of S. flaccidus. The restriction to gypseous soils and the gross aspect combine to make it distinctive.

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

Source FNA vol. 20, p. 566. FNA vol. 20, p. 559.
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. wootonii
Synonyms S. gibbonsii, S. saliens, S. triangularis var. angustifolius
Name authority Hooker: Fl. Bor.-Amer. 1: 332, plate 115. (1834) Shinners: Sida 1: 379. (1964)
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