Senecio integerrimus |
Senecio mohavensis |
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lambstongue ragwort, mountain butterweed, one-stem butterweed, tall western groundsel, western groundsel |
Mohave groundsel, Mojave ragwort |
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Habit | Perennials (possibly biennials), (10–)20–70 cm (caudices buttonlike, roots fleshy-fibrous). | Annuals, 10–30(–40) cm (taproots often twisted). | ||||||||||||||||
Herbage | arachnose, loosely tomentose, or villous (hairs crisped, jointed), glabrescent. |
(sometimes purple-tinged) glabrous. |
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Stems | single. |
usually 1 (freely branching upward). |
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Leaves | progressively reduced distally; ± petiolate; blades elliptic, lanceolate, linear, oblanceolate, rounded-deltate, or suborbiculate, 6–25 × 1–6 cm, bases ± tapered or truncate to cordate, margins entire or ± dentate (distal leaves sessile, bractlike). |
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). |
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Ray florets | usually ± 8 or ± 13, sometimes 0; corolla laminae 6–15(–20) mm (usually yellow, ochroleucous to white in one variety). |
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). |
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Phyllaries | usually ± 13 or ± 21, rarely ± 8, (4–)5–12(–15) mm, tips usually black, sometimes green. |
± 8 or ± 13, 6–7 mm, tips green. |
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Calyculi | of 1–5+ linear to filiform bractlets (seldom more than 2 mm). |
of 3–5+ lance-linear bractlets. |
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Heads | 6–20(–40+) in corymbiform arrays (peduncle of terminal head often shorter than others). |
3–10 in loose, cymiform arrays. |
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Cypselae | usually glabrous, sometimes hirtellous (mostly on angles). |
hairy. |
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2n | = 40, 80. |
= 40. |
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Senecio integerrimus |
Senecio mohavensis |
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Phenology | Flowering spring. | |||||||||||||||||
Habitat | Sandy or rocky washes, desert flats | |||||||||||||||||
Elevation | 100–700 m (300–2300 ft) | |||||||||||||||||
Distribution |
CA; CO; IA; ID; KS; MN; MT; ND; NE; NM; NV; OR; SD; UT; WA; WY; AB; BC; MB; SK
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AZ; CA; NV; Mexico (Sonora)
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Discussion | Varieties 5 (5 in the flora). The varieties of Senecio integerrimus are distinguished by morphology and geography. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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Key |
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Source | FNA vol. 20, p. 556. | FNA vol. 20, p. 563. | ||||||||||||||||
Parent taxa | Asteraceae > tribe Senecioneae > Senecio | Asteraceae > tribe Senecioneae > Senecio | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Name authority | Nuttall: Gen. N. Amer. Pl. 2: 165. (1818) | Torrey & A. Gray: in A. Gray et al., Syn. Fl. N. Amer. 1(2): 446. (1884) | ||||||||||||||||
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