Flora of North America species comparison

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Senecio sylvaticus

Senecio fremontii

heath groundsel, wood groundsel, woodland groundsel, woodland ragwort

dwarf mountain butterweed, dwarf mountain ragwort, Fremont's groundsel, Fremont's ragwort
Habit Annuals, (15–)30–80+ cm (taproots fibrous-rooted). Perennials, 10–30(–40) cm (perennating bases subrhizomatous, spreading, sometimes knotty-woody).
Herbage

puberulent (hairs abundant, curly).

(often purple-tinged) glabrous.
Stems

single.

clustered (arching upward to semiprostrate).
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 or smaller and fewer distally (somewhat stiffish-succulent when fresh, proximalmost and distalmost often smaller, bractlike); petiolate;

blades ovate or obovate to oblanceolate, 2–5(–7) × 1–3(–4) cm, bases ± truncate to tapered, margins laciniate to dentate or subentire.
Ray florets

0 or 1–8+;

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

± 8;

corolla laminae 8–12 mm.
Phyllaries

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

(± 8) ± 13 (± 21), 5–12 mm, tips green or brownish.
Calyculi

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

0 or of 1–5+ usually lance-deltate to linear, sometimes foliaceous, bractlets (lengths mostly 1/5–1/2 phyllaries).
Heads

12–24 in corymbiform arrays.

1–5+.
Cypselae

hairy (especially on angles).

glabrous or strigose-hirtellous, at least on angles.
2n

= 40.

= 40, 40+, 80.

Senecio sylvaticus

Senecio fremontii
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; AB; 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.)

Varieties 4 (4 in the flora).

The varieties are distinguished by morphologic tendencies plus their geographic ranges.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Plants (10–)25–40 cm; stems straight or gently arching upward; leaves often to 7 × 3 cm, bases of larger ones weakly clasping; phyllaries (9–)10–12 mm
var. blitoides
1. Plants 10–20+ cm; stems usually arching upward; leaves usually smaller than 4 × 2 cm, bases not clasping; phyllaries 5–10 mm
→ 2
2. Leaf margins notably laciniate or laciniate-toothed (segments sometimes also toothed)
var. inexpectatus
2. Leaf margins toothed or subentire
→ 3
3. Leaves smaller and fewer distally; phyllaries 5–7(–8) mm
var. occidentalis
3. Leaves ± equally developed along stems; phyllaries (7–)8–10 mm
var. fremontii
Source FNA vol. 20, p. 563. FNA vol. 20, p. 564.
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. 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
Subordinate taxa
S. fremontii var. blitoides, S. fremontii var. fremontii, S. fremontii var. inexpectatus, S. fremontii var. occidentalis
Synonyms S. ductoris
Name authority Linnaeus: Sp. Pl. 2: 868. (1753) Torrey & A. Gray: Fl. N. Amer. 2: 445. (1843)
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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