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alkali marsh groundsel, alkali-marsh butterweed, alkali-marsh ragwort, water groundsel, water ragwort

Senecio neowebsteri

Olympic Mountain ragwort

Habit Perennials (biennials?), 40–100(–200) cm (caudices foreshortened, roots fleshy-fibrous). Perennials, 7–15(–20+) cm (rhizomes fibrous-rooted).
Herbage

(often sea-green, usually glaucous) glabrous.

(sometimes purplish-tinged) floccose-tomentose, unevenly glabrescent.

Stems

single or 2–4 loosely clustered.

single or loosely clustered (erect or arching).

Leaves

progressively reduced distally; ± petiolate;

blades elliptic to oblanceolate, 5–20+ × (1–)2–10 cm, bases tapered, margins denticulate or entire (mid and distal leaves sessile, bractlike).

mostly cauline;

petiolate (petioles about equaling blades);

blades lanceolate or oblanceolate to ovate, (2–)4–8+ × 1.5–3 cm, bases tapered, margins denticulate (distal leaves smaller, lanceolate or linear-lanceolate, bractlike).

Ray florets

(0) ca. 5;

corolla laminae 3–5 mm.

± 13;

corolla laminae ± 15 mm.

Phyllaries

± 8 or ± 13, 5–8 mm, tips frequently black.

usually ± 21, sometimes ± 13, (8–)10–15 mm, tips usually greenish (often sparsely hairy).

Calyculi

of 2–4+ bractlets (less than 2 mm).

of 4–8 lanceolate to lance-linear bractlets (lengths mostly less than 1/2 phyllaries).

Heads

20–40(–80+) in compound corymbiform arrays.

nodding, 1(–2).

Cypselae

glabrous.

glabrous.

2n

= 40.

= 40.

Senecio hydrophilus

Senecio neowebsteri

Phenology Flowering spring–early summer. Flowering late summer–early fall.
Habitat Marshes, swampy places, standing water, alkaline sites High talus slopes
Elevation (0–)200–2500 m ((0–)700–8200 ft) 2200–2600 m (7200–8500 ft)
Distribution
from FNA
CA; CO; ID; MT; NV; OR; SD; UT; WA; WY; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

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

Source FNA vol. 20, p. 557. FNA vol. 20, p. 553.
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. 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
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. 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. hydrophilus var. pacificus S. websteri
Name authority Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 411. (1841) S. F. Blake: Leafl. W. Bot. 8: 143. (1957)
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