Euphorbia agraria |
Euphorbia pubentissima |
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urban spurge |
false flowering spurge, southeastern flowering spurge |
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Habit | Herbs, perennial, with slender, spreading rootstock. | Herbs, perennial, with spreading rootstock. |
Stems | erect or ascending, unbranched or branched, 30–90 cm, glabrous. |
erect, usually unbranched, occasionally few branched distally, solitary or few, previous year's dead stems not persistent, 30–65 cm, usually glabrous, rarely villous. |
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 1 mm; petiole (0–)1–2(–10) mm, glabrous or densely villous; blade lanceolate, lance-ovate, elliptic, or obovate, 40–68 × 6–18 mm, often reflexed, base cuneate to rounded, margins entire, apex usually rounded, sometimes broadly acute, abaxial surface glabrous or villous, adaxial surface usually glabrous, rarely sparsely villous; venation occasionally obscure on small leaves, 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 or hemispheric, 1.3–1.7 × 1.8–2.2 mm, glabrous or villous; glands 5 (7–10 on central cyathium), green, reniform or broadly elliptic, 0.3–0.5 × 0.5–0.8 mm; appendages white, orbiculate or narrowly flabellate, 1–2.2 × 1.5 mm, entire. |
Staminate flowers | 15–20. |
20–25. |
Pistillate flowers | ovary glabrous; styles 1.2–2 mm, 2-fid. |
ovary glabrous or sparsely villous; styles 0.6–1.1 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. |
globose, 2–2.4 × 3.3–4.8 mm, glabrous or sparsely villous; columella 1.8–2.1 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. |
light gray, ovoid, 2.2–2.4 × 1.6–1.8 mm, with shallow depressions; 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; peduncle 1–5 mm (or 15–40 mm on early flowering individuals), usually glabrous, occasionally sparsely villous. |
Euphorbia agraria |
Euphorbia pubentissima |
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Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring–fall. |
Habitat | Grasslands, roadside banks, pastures. | Open fields, cliffs, woods, floodplains. |
Elevation | 200–1600 m. (700–5200 ft.) | 0–900 m. (0–3000 ft.) |
Distribution |
KS; MT; NE; NY; PA; WA; WY; AB; SK; Europe [Introduced in North America]
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AL; FL; GA; LA; MD; MS; NC; SC; TN; VA; WV
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Discussion | The taxonomic history of Euphorbia pubentissima is complex. The species has been included within a very broadly defined E. corollata in the past. Therefore, its geographic distribution appears significantly more wide-ranging in some treatments. The framework established by M. J. Huft (1979) and later by K. R. Park (1998) is followed here. Euphorbia pubentissima is recognized as a variable species restricted to the southeastern United States. The species can be distinguished from E. corollata by its shorter involucral gland appendages and smaller seeds. Euphorbia paniculata Elliott, which sometimes is applied to E. pubentissima, is an illegitimate name (a later homonym of Euphorbia paniculata Desfontaines). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 250. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Tithymalus agrarius | E. apocynifolia, E. corollata var. paniculata, E. corollata var. zinniiflora, E. zinniiflora, Tithymalopsis apocynifolia, T. paniculata, T. zinniiflora |
Name authority | M. Bieberstein: Fl. Taur.-Caucas. 1: 375. (1808) | Michaux: Fl. Bor.-Amer. 2: 212. (1803) |
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