Euphorbia agraria |
Euphorbia lurida |
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urban spurge |
woodland spurge |
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Habit | Herbs, perennial, with slender, spreading rootstock. | Herbs, perennial, with thick rootstock. |
Stems | erect or ascending, unbranched or branched, 30–90 cm, glabrous. |
erect or ascending, unbranched, sometimes sinuous, 5–30 cm, glabrous or sparsely to densely puberulent. |
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. |
petiole 0–1 mm; blade oblanceolate to obovate, 8–20 mm × 3–7 mm, base truncate or cuneate, margins entire, apex obtuse to rounded, minutely mucronate, surfaces puberulent or glabrous; venation inconspicuous, only midvein prominent. |
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. |
cupulate, 2–2.2 × 1.3–1.8 mm, glabrous; glands 4, oblong to broadly ovate, usually truncate, 0.5–0.8 × 1–1.6 mm, margins irregularly crenate to strongly dentate; horns absent or usually divergent or straight, 0.1–0.3 mm, usually slightly longer than, occasionally equaling, teeth on gland margin. |
Staminate flowers | 15–20. |
10–20. |
Pistillate flowers | ovary glabrous; styles 1.2–2 mm, 2-fid. |
ovary glabrous or puberulent; styles 0.7–1 mm, 2-fid. |
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. |
ovoid, 3.5–4 × 4–4.5 mm, 3-lobed; cocci rounded, smooth to slightly rugose, glabrous; columella 3.2–3.5 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. |
gray to dark gray, truncate-oblong to truncate-ovoid, 2.8–3 × 1.7–2 mm, irregularly pitted; caruncle conic, 0.6 × 0.7 mm. |
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. |
arrangement: terminal pleiochasial branches 3–5, each 1–4 times 2-branched; pleiochasial bracts ovate to broadly ovate or oblanceolate, wider than distal leaves; dichasial bracts distinct, rounded, oblanceolate, or subreniform, base cuneate or obtuse, margins entire, apex obtuse, slightly mucronate; axillary cymose branches 0–4. |
Cyathia | peduncle 0–2 mm. |
peduncle 0.3–0.9 mm. |
Euphorbia agraria |
Euphorbia lurida |
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Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring–summer. |
Habitat | Grasslands, roadside banks, pastures. | Open pine-oak forests, dry slopes and canyons. |
Elevation | 200–1600 m. (700–5200 ft.) | 1300–2800 m. (4300–9200 ft.) |
Distribution |
KS; MT; NE; NY; PA; WA; WY; AB; SK; Europe [Introduced in North America]
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AZ; CA; NM; NV; UT; Mexico (Baja California)
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Discussion | Euphorbia lurida has been treated as a complex of several taxa in the past, but only a single, broadly-defined species is recognized here. This species is variable in both the pubescence and shape of the bracts subtending the cyathia and also in the degree of crenation of the gland margin. In the northern part of its range, E. lurida appears to intergrade with E. brachycera, and it can be difficult to distinguish these two species in northern Arizona and New Mexico. A report of the species from Sonora, Mexico, based on a single immature collection (V. W. Steinmann and R. S. Felger 1997) has not been verified. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 305. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Tithymalus agrarius | E. palmeri, E. palmeri var. subpubens, E. subpubens, Tithymalus luridus, T. palmeri, T. subpubens |
Name authority | M. Bieberstein: Fl. Taur.-Caucas. 1: 375. (1808) | Engelmann: in J. C. Ives, Rep. Colorado R. 4: 26. (1861) |
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