Flora of North America species comparison

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Senecio sylvaticus

Senecio serra

heath groundsel, wood groundsel, woodland groundsel, woodland ragwort

butterweed groundsel, sawtooth groundsel, serrated ragwort, tall butterweed, tall ragwort
Habit Annuals, (15–)30–80+ cm (taproots fibrous-rooted). Perennials, 40–100(–250) cm (caudices ligneous, branched).
Herbage

puberulent (hairs abundant, curly).

glabrous or lightly floccose-tomentose proximally when young.
Stems

single.

single or 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).

evenly distributed (proximal often withering before flowering); petiolate or subsessile;

blades lanceolate or narrowly lanceolate to sublinear, 5–15(–20+) × (1–)1.5–4 cm, bases tapered, margins dentate to subentire (distal leaves smaller, bractlike).
Ray florets

0 or 1–8+;

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

± 5 or ± 8;

corolla laminae 5–10 mm.
Phyllaries

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

± 8 or ca. 13, 4–9 mm, tips usually green, sometimes black.
Calyculi

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

of 2–6 linear to filiform bractlets (0.5–5 mm).
Heads

12–24 in corymbiform arrays.

30–90+ in corymbiform to subpaniculiform arrays.
Cypselae

hairy (especially on angles).

glabrous or glabrate.
2n

= 40.

= 40.

Senecio sylvaticus

Senecio serra
Phenology Flowering late spring–summer (northern areas of cool, climate); winter (southern areas).
Habitat Mildly disturbed woodlands, open, sandy sites
Elevation 100–300 m (300–1000 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; UT; WA; WY
[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.)

Varieties 2 (2 in the flora).

Varieties of Senecio serra are distinguished by head size and distribution.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Heads 40–90+; phyllaries ± 8, 4–6 mm; ray florets ± 5, corolla laminae 5–7 mm; disc florets 10–20
var. serra
1. Heads (12–)30–50; phyllaries ± 13, 7–9 mm; ray florets ± 8, corolla laminae 7–10 mm; disc florets 20–40+
var. admirabilis
Source FNA vol. 20, p. 563. FNA vol. 20, p. 566.
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. 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. 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
Subordinate taxa
S. serra var. admirabilis, S. serra var. serra
Name authority Linnaeus: Sp. Pl. 2: 868. (1753) Hooker: Fl. Bor.-Amer. 1: 333. (1834)
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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