Euphorbia agraria |
Euphorbia marginata |
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urban spurge |
euphorbe marginée, mountain snow spurge, smoke-on-the-prairie, snow-on-the-mountain, variegated spurge, whitemargined spurge |
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Habit | Herbs, perennial, with slender, spreading rootstock. | Herbs, annual, with taproot. |
Stems | erect or ascending, unbranched or branched, 30–90 cm, glabrous. |
erect, unbranched or branched, 30–85(–150) cm, pilose or glabrous. |
Leaves | petiole absent; blade oblong-elliptic, 20–65 × 9–20 mm, base truncate to auriculate, margins entire, apex obtuse to rounded, surfaces glabrous; venation conspicuously pinnate, midvein prominent. |
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. |
Involucre | campanulate, 2.2–3 × 1.8–2 mm, glabrous; glands 4, crescent-shaped; 0.6–1 × 1–2 mm; horns slightly divergent to convergent, 0.1–0.2 mm. |
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. |
Staminate flowers | 15–20. |
30–70. |
Pistillate flowers | ovary glabrous; styles 1.2–2 mm, 2-fid. |
ovary pilose; styles 1–2.5 mm, 2-fid 1/2–2/3 length. |
Capsules | globose, 2–2.8 × 2.2–2.7 mm, 3-lobed; cocci rounded, smooth except finely granulate toward abaxial line, glabrous; columella 2.1–2.7 mm. |
oblate, 3–5 × 3.5–7.5 mm, moderately to densely pilose; columella 3–4.1 mm. |
Seeds | gray or whitish, ovoid-oblong, 2–2.1 × 1.2–1.3 mm, smooth; caruncle ± rounded and flattened, 0.8 × 0.6 mm. |
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. |
Cyathial | arrangement: terminal pleiochasial branches 8–15, 1–2 times 2-branched; pleiochasial bracts similar in shape but shorter and narrower than distal leaves; dichasial bracts distinct, rhombic to reniform, base obtuse, margins entire, apex obtuse, mucronate; axillary cymose branches 12–23. |
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Cyathia | peduncle 0–2 mm. |
in terminal pleiochasia, dichasial bracts narrowly elliptic to oblanceolate with conspicuous white margins; peduncle 1.8–2.7(–22) mm, densely pilose. |
2n | = 56. |
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Euphorbia agraria |
Euphorbia marginata |
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Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting summer–fall. |
Habitat | Grasslands, roadside banks, pastures. | Disturbed areas and grasslands. |
Elevation | 200–1600 m. (700–5200 ft.) | 0–1700 m. (0–5600 ft.) |
Distribution |
KS; MT; NE; NY; PA; WA; WY; AB; SK; Europe [Introduced in North America]
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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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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.) |
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Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 248. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Tithymalus agrarius | E. bonplandii, Lepadena marginata |
Name authority | M. Bieberstein: Fl. Taur.-Caucas. 1: 375. (1808) | Pursh: Fl. Amer. Sept. 2: 607. (1813) |
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