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Elmer's butterweed, Elmer's ragwort

Mohave groundsel, Mojave ragwort

Habit Perennials, 10–20(–30) cm (rhizomes trailing or branching). Annuals, 10–30(–40) cm (taproots often twisted).
Herbage

unevenly villous-tomentose or floccose, glabrescent.

(sometimes purple-tinged) glabrous.

Stems

single (from loosely clustered basal leaves).

usually 1 (freely branching upward).

Leaves

progressively reduced distally; ± petiolate;

blades ovate to oblanceolate, (3–)4–8(–10) × 2–3(–4) cm, bases tapered, margins shallowly dentate (mid and distal leaves smaller, bractlike, often clasping).

equally distributed; petiolate;

blades ovate to obovate, 2–6 × 0.5–2(–4) cm, bases tapered, margins coarsely lobed or irregularly dentate (mid and distal leaves similar, bases expanded, truncate to cordate, clasping, 1–2 cm across).

Ray florets

± 8;

corolla laminae 8–15 mm.

0 or 1–3+;

corolla laminae 0.1–1 mm (little expanded, barely, if at all, surpassing phyllaries; sometimes laminae 0 and heads perhaps technically disciform).

Phyllaries

(± 8) ± 13, 8–10 mm, tips black (villous).

± 8 or ± 13, 6–7 mm, tips green.

Calyculi

of 2–7 lance-linear to linear bractlets (lengths 1/3–2/3 phyllaries).

of 3–5+ lance-linear bractlets.

Heads

erect or weakly nodding (especially in bud), (2–)5–9(–12) in loose, cymiform arrays.

3–10 in loose, cymiform arrays.

Cypselae

glabrous.

hairy.

2n

= 40.

= 40.

Senecio elmeri

Senecio mohavensis

Phenology Flowering summer. Flowering spring.
Habitat Alpine and subalpine rocky sites and talus slopes Sandy or rocky washes, desert flats
Elevation 2000–3000 m (6600–9800 ft) 100–700 m (300–2300 ft)
Distribution
from FNA
WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV; Mexico (Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Senecio mohavensis is similar to S. flavus (Decaisne) Schultz-Bipontinus of the Mediterranean region and southwest Asia, which raises phytogeographic questions (cf. A. Liston et al. 1989; Liston and J. W. Kadereit 1995; M. Coleman et al. 2001). The last cited study showed that a previously recognized variety of S. flavus is more closely related to S. mohavensis than to S. flavus and a new combination was made: S. mohavensis subsp. brevifolius (Kadereit) M. Coleman.

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

Source FNA vol. 20, p. 551. FNA vol. 20, p. 563.
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. 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. 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. crepidineus
Name authority Piper: Erythea 7: 173. (1899) Torrey & A. Gray: in A. Gray et al., Syn. Fl. N. Amer. 1(2): 446. (1884)
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