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heath groundsel, wood groundsel, woodland groundsel, woodland ragwort

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

Habit Annuals, (15–)30–80+ cm (taproots fibrous-rooted). Perennials (biennials?), 40–100(–200) cm (caudices foreshortened, roots fleshy-fibrous).
Herbage

puberulent (hairs abundant, curly).

(often sea-green, usually glaucous) glabrous.

Stems

single.

single or 2–4 loosely clustered.

Leaves

evenly distributed; petiolate;

blades obovate to oblong, 3–7(–12) × 1–3(–4) cm, usually 1–2-pinnate, bases tapered, ultimate margins dentate (distal leaves similar, clasping, bractlike).

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).

Ray florets

0 or 1–8+;

corolla laminae usually 1–2+ mm (barely surpassing phyllaries).

(0) ca. 5;

corolla laminae 3–5 mm.

Phyllaries

± 13 (± 21), 4–7+ mm, tips greenish or minutely black.

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

Calyculi

0 or of 1–5+ linear to filiform bractlets.

of 2–4+ bractlets (less than 2 mm).

Heads

12–24 in corymbiform arrays.

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

Cypselae

hairy (especially on angles).

glabrous.

2n

= 40.

= 40.

Senecio sylvaticus

Senecio hydrophilus

Phenology Flowering late spring–summer (northern areas of cool, climate); winter (southern areas). Flowering spring–early summer.
Habitat Mildly disturbed woodlands, open, sandy sites Marshes, swampy places, standing water, alkaline sites
Elevation 100–300 m (300–1000 ft) (0–)200–2500 m ((0–)700–8200 ft)
Distribution
from FNA
CA; LA; MA; MI; NJ; OH; OR; PA; WA; WI; BC; NB; NF; NS; PE; QC; Eurasia [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CO; ID; MT; NV; OR; SD; UT; WA; WY; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

Senecio sylvaticus is a Eurasian weed that favors cool, wet climates. It is well established in coastal areas of the Pacific Coast and in parts of Newfoundland and Quebec; elsewhere in the flora, it appears to be sporadic.

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

Source FNA vol. 20, p. 563. FNA vol. 20, p. 557.
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. 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. 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. hydrophilus var. pacificus
Name authority Linnaeus: Sp. Pl. 2: 868. (1753) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 411. (1841)
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