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San Gabriel ragwort

butterweed groundsel, sawtooth groundsel, serrated ragwort, tall butterweed, tall ragwort

Habit Perennials, 40–100 cm (caudices unknown). Perennials, 40–100(–250) cm (caudices ligneous, branched).
Herbage

unevenly floccose-lanate or tomentose, glabrescent.

glabrous or lightly floccose-tomentose proximally when young.

Stems

single.

single or loosely clustered.

Leaves

progressively reduced distally;

petiolate;

blades elliptic-ovate to lanceolate, 10–20(–30?) × 3–7+ cm, bases tapered, margins dentate to denticulate (teeth cartilaginous; mid leaves similar, sessile, smaller; distal leaves 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.

± 5 or ± 8;

corolla laminae 5–10 mm.

Phyllaries

± 21, 7–8 mm, tips greenish.

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

Calyculi

of 5–8+ lance-linear to filiform bractlets (lengths 1/3–7/8 phyllaries).

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

Heads

10–20+ in loose or congested, cymiform arrays.

30–90+ in corymbiform to subpaniculiform arrays.

Cypselae

glabrous.

glabrous or glabrate.

2n

= 40.

= 40.

Senecio astephanus

Senecio serra

Phenology Flowering spring.
Habitat Steep, rocky slopes
Elevation 400–1500 m (1300–4900 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Senecio astephanus is collected infrequently.

(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. 553. 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. 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. 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 Greene: Pittonia 1: 174. (1888) Hooker: Fl. Bor.-Amer. 1: 333. (1834)
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