Euphorbia marginata |
Euphorbia helioscopia |
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euphorbe marginée, mountain snow spurge, smoke-on-the-prairie, snow-on-the-mountain, variegated spurge, whitemargined spurge |
euphorbe réveille-matin, mad woman's milk, summer spurge, sun spurge, wart spurge, wartweed |
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Habit | Herbs, annual, with taproot. | Herbs, annual, with taproot. |
Stems | erect, unbranched or branched, 30–85(–150) cm, pilose or glabrous. |
erect, unbranched or branched, 5–45 cm, usually glabrous or sparsely pilose. |
Leaves | alternate; stipules 0.1–0.3 mm; petiole 0.2–3 mm, glabrous or minutely pilose; blade broadly ovate to elliptic, 32–62(–82) × 18–28(–52) mm, base rounded to cuneate, margins entire, often white on distal leaves, apex acute, rarely mucronate, surfaces glabrous; venation obscure, only midvein conspicuous. |
petiole absent or to 0.5 mm; blade obovate-spatulate, 4–40 × 2–25 mm, base cuneate, attenuate, or auriculate, margins serrulate, apex rounded, surfaces glabrous; venation pinnate, midvein prominent. |
Involucre | campanulate, 2.2–3.5 × 1.3–2.3 mm, margin between glands deeply divided into fringe of fimbriate lobes, pilose; glands 4–5, green to greenish yellow, reniform to subcircular, 0.7–1.1 × 1–1.6 mm; appendages white, orbiculate, 1.5–2.7 × 1.9–2.9(–3.6) mm, entire. |
cupulate, 1.5–2 × 0.7–1.1 mm, glabrous; glands 4, elliptic, 0.2–0.5 × 0.5–1 mm; horns absent. |
Staminate flowers | 30–70. |
10–15. |
Pistillate flowers | ovary pilose; styles 1–2.5 mm, 2-fid 1/2–2/3 length. |
ovary glabrous; styles 0.7–1 mm, 2-fid. |
Capsules | oblate, 3–5 × 3.5–7.5 mm, moderately to densely pilose; columella 3–4.1 mm. |
depressed-globose, 2.5–4 × 3.2–4.2 mm, clearly 3-lobed; cocci rounded, smooth, glabrous; columella 0.9–1.1 mm. |
Seeds | orange-tan to gray, ovoid, 3.7–3.9 × 3–3.3 mm, rugose, with 2 transverse ridges (one dark orange to brown, other inconspicuous); caruncle absent. |
dark brown to blackish, subovoid, 1.6–2.2 × 1.5–1.9 mm, reticulate; caruncle elliptic, 0.9–1.1 × 0.4–0.5 mm. |
Cyathia | in terminal pleiochasia, dichasial bracts narrowly elliptic to oblanceolate with conspicuous white margins; peduncle 1.8–2.7(–22) mm, densely pilose. |
peduncle 0.2–1 mm. |
Cyathial | arrangement: terminal pleiochasial branches (3–)5, each 1–2 times 2-branched; pleiochasial bracts obovate, wider than distal leaves; dichasial bracts distinct, obovate or rhombic, ± oblique, base rounded, truncate, or attenuate, margins serrulate, apex rounded; axillary cymose branches 0. |
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2n | = 56. |
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Euphorbia marginata |
Euphorbia helioscopia |
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Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting spring–fall. |
Habitat | Disturbed areas and grasslands. | Roadsides, waste places. |
Elevation | 0–1700 m. (0–5600 ft.) | 0–1400 m. (0–4600 ft.) |
Distribution |
AR; CA; CO; CT; IA; IL; IN; KS; LA; MA; MD; MI; MN; MO; MT; NC; NE; NH; NM; NY; OH; OK; PA; RI; SC; SD; TN; TX; UT; VA; WI; WV; WY; MB; ON; QC; SK; c Mexico; s Mexico
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CA; CT; DC; DE; GA; ID; IL; LA; MA; MD; ME; MI; MT; NC; NH; NJ; NY; OH; OR; PA; SC; TN; TX; VA; VT; WA; WI; WY; AB; BC; NB; NF; NS; ON; PE; QC; SK; Europe; Asia; n Africa [Introduced in North America; introduced also in South America (Argentina, Chile)]
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Discussion | Euphorbia marginata is native to the central United States. The type specimen was collected by Meriwether Lewis along the Yellowstone River in southern Montana in 1806, and it has been reported to be native as far south as Arizona, New Mexico, and Texas, and as far east as southern Minnesota, western Iowa, and Missouri (G. Yatskievych 1999–2013, vol. 2). It is presumably naturalized outside of this area. Euphorbia marginata is widely cultivated as an ornamental for its showy, white-margined distal leaves, and it can escape locally. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia helioscopia was collected once in Minnesota in the late 1800s but apparently did not become established there. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 248. | FNA vol. 12, p. 303. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | E. bonplandii, Lepadena marginata | Galarhoeus helioscopius, Tithymalus helioscopius |
Name authority | Pursh: Fl. Amer. Sept. 2: 607. (1813) | Linnaeus: Sp. Pl. 1: 459. (1753) |
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