Euphorbia agraria |
Euphorbia trachysperma |
|
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urban spurge |
San Pedro River sandmat |
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Habit | Herbs, perennial, with slender, spreading rootstock. | Herbs, annual, with slender taproot. |
Stems | erect or ascending, unbranched or branched, 30–90 cm, glabrous. |
erect to ascending, 10–55 cm, 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. |
opposite; stipules distinct, narrowly triangular and often divided into 3–5 subulate to filiform segments, 0.8–1.9 mm, glabrous; petiole 1.2–3.1 mm, glabrous; blade oblong, elliptic, or ovate, 12–43 × 3–14 mm, base subsymmetric to asymmetric, rounded, attenuate, or with one side hemicordate and other side rounded, margins usually serrulate, rarely entire on some leaves or portion of blade, apex obtuse to acute, surfaces often with red blotch in center, glabrous; pinnately veined, often 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. |
oblong, campanulate, or funnel-shaped, 1.5–2.6 × 1.1–2.3 mm, glabrous; glands 4, green to yellowish or tinged with red, subcircular to oblong, 0.4–0.7 × 0.5–1 mm; appendages absent or white, often forming narrow rim or oblong to ovate, 0–0.8 × 1.2 mm, distal margin entire. |
Staminate flowers | 15–20. |
50–60. |
Pistillate flowers | ovary glabrous; styles 1.2–2 mm, 2-fid. |
ovary glabrous; styles 0.5–0.6 mm, 2-fid 1/2 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, 2.4–3.2 × 3–3.5 mm, glabrous; columella 2.3–2.5 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. |
light brown, ovoid, 4-angled in cross section, abaxial keel well developed, 1.9–2.3 × 1.3–1.4 mm, finely dimpled and papillate. |
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. |
|
Cyathia | peduncle 0–2 mm. |
solitary at distal nodes; peduncle 1.4–2.4 mm. |
Euphorbia agraria |
Euphorbia trachysperma |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting late summer–early winter. |
Habitat | Grasslands, roadside banks, pastures. | Desert scrub, desert grasslands, mesquite woodlands. |
Elevation | 200–1600 m. (700–5200 ft.) | 200–1200 m. (700–3900 ft.) |
Distribution |
KS; MT; NE; NY; PA; WA; WY; AB; SK; Europe [Introduced in North America]
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AZ; Mexico (Baja California Sur, Sonora) |
Discussion | Euphorbia trachysperma may be expected in extreme southwestern New Mexico given the close proximity of some collections in southeastern Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 291. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus agrarius | Chamaesyce trachysperma |
Name authority | M. Bieberstein: Fl. Taur.-Caucas. 1: 375. (1808) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) |
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