Euphorbia marginata |
Euphorbia setiloba |
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euphorbe marginée, mountain snow spurge, smoke-on-the-prairie, snow-on-the-mountain, variegated spurge, whitemargined spurge |
fringe spurge, shaggy spurge, Yuma sandmat |
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Habit | Herbs, annual, with taproot. | Herbs, annual, with slender taproot. |
Stems | erect, unbranched or branched, 30–85(–150) cm, pilose or glabrous. |
prostrate, mat-forming, 5–50 cm, villous with glistening glandular hairs. |
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. |
opposite; stipules distinct, filiform, rudimentary to 0.2 mm, glabrous or sparsely villous with glistening glandular hairs; petiole 0.5–1.5 mm, villous; blade oblong, ovate, or elliptic, 3–7 × 2–4 mm, base asymmetric, rounded, margins entire, apex obtuse, surfaces villous; weakly 3-veined from base, commonly only midvein conspicuous. |
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. |
campanulate or urceolate, 0.7–1 × 0.5–0.8 mm, villous; glands 4, red to pink, oblong to slightly reniform, 0.1–0.2 × 0.2–0.3 mm; appendages white to pink, deeply incised into 3–6 triangular to subulate, attenuate, acute segments, 0.3–0.6 × 0.6–1 mm, segments entire. |
Staminate flowers | 30–70. |
3–7. |
Pistillate flowers | ovary pilose; styles 1–2.5 mm, 2-fid 1/2–2/3 length. |
ovary villous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
Capsules | oblate, 3–5 × 3.5–7.5 mm, moderately to densely pilose; columella 3–4.1 mm. |
subglobose to ovoid, 1–1.2 mm diam., villous; 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. |
pink to light gray, narrowly ovoid, 4-angled in cross section, 0.8–1 × 0.5–0.6 mm, dimpled or with faint transverse ridges that do not pass through abaxial keel. |
Cyathia | in terminal pleiochasia, dichasial bracts narrowly elliptic to oblanceolate with conspicuous white margins; peduncle 1.8–2.7(–22) mm, densely pilose. |
solitary at distal nodes, nodes often congested toward tips of branches; peduncle 0.2–1.6 mm. |
2n | = 56. |
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Euphorbia marginata |
Euphorbia setiloba |
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Phenology | Flowering and fruiting summer–fall. | Flowering nearly year-round in response to sufficient moisture. |
Habitat | Disturbed areas and grasslands. | Desert scrub, blackbrush scrub, Joshua tree woodlands, grasslands, often in sandy areas. |
Elevation | 0–1700 m. (0–5600 ft.) | 20–1600 m. (100–5200 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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AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Baja California Sur, Chihuahua, Durango, Sinaloa, Sonora)
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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. 248. | FNA vol. 12, p. 288. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | E. bonplandii, Lepadena marginata | Chamaesyce setiloba |
Name authority | Pursh: Fl. Amer. Sept. 2: 607. (1813) | Engelmann: in War Department [U.S.], Pacif. Railr. Rep. 5(2): 364. (1857) |
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