Euphorbia alta |
Euphorbia ocellata |
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giant spurge, roughpod spurge, tall spurge, warty spurge |
Contura Creek sandmat, Contura Creek spurge, valley spurge |
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Habit | Herbs, annual or biennial, with taproot. | Herbs, annual, with taproot. | ||||
Stems | erect, branched, 20–60 cm, glabrous. |
prostrate, 10–35 cm, glabrous or pilose. |
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Leaves | petiole 0–1 mm; blade oblong-spatulate, 20–50 × 7–18 mm, base broadly attenuate, margins serrulate, apex rounded to obtuse, surfaces glabrous, ± glaucous; venation pinnate, midvein prominent. |
opposite; stipules distinct, subulate, 0.5–1.6 mm, glabrous or pilose; petiole 0.3–2 mm, glabrous or pilose; blade ovate to deltate or falcate, 2.3–13 × 1.5–6 mm, base asymmetric, usually cordate, rarely rounded, margins occasionally reddish, entire, often revolute, apex acute to obtuse, occasionally mucronate, surfaces glabrous or pilose; midvein conspicuous, lateral veins frequently visible abaxially. |
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Involucre | narrowly campanulate, 0.8–1.1 × 1.1–1.3 mm, glabrous; glands 4, elliptic, 0.3–0.5 × 0.5–0.7 mm; horns absent. |
campanulate, 1–2.5 × 1.3–2.4 mm, glabrous or pilose; glands 4, yellow becoming deep red, elliptic or oblong to orbiculate, 0.4–0.6 × 0.5–0.7 mm; appendages absent or whitish, orbiculate, 0.1–0.2 × 0.3–0.5 mm, distal margin entire. |
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Staminate flowers | 5–10. |
30–70. |
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Pistillate flowers | ovary glabrous; styles 0.5–0.9 mm, 2-fid. |
ovary glabrous or pilose; styles 0.4–0.5 mm, 2-fid at apex. |
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Capsules | depressed-globose, 2–3 × 2.5–3.5 mm, 3-lobed; cocci rounded, papillate, papillae 0.2–0.5 mm, glabrous; columella 1.5–1.9 mm. |
subglobose to broadly ovoid, 1.4–2.7 × 1.9–3.1 mm, glabrous or pilose; columella 1.4–2 mm. |
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Seeds | purple-black, ovoid, 1.6–2 × 1.3–1.7 mm, reticulate and areolate; caruncle reniform, flat, 0.5 × 0.7 mm. |
whitish gray to black, ovoid to oblong, terete to bluntly subangled in cross section, 1.1–1.7 × 0.8–1.3 mm, rugose or smooth. |
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Cyathial | arrangement: terminal pleiochasial branches 3, 2–3 times 2-branched; pleiochasial bracts elliptic-oblanceolate to oblong, similar in size to distal leaves; dichasial bracts distinct, broadly ovate to orbiculate/reniform, base obtuse, margins serrulate, apex obtuse to rounded and often mucronulate; axillary cymose branches 6–20(–25). |
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Cyathia | peduncle 0.5–1 mm. |
solitary at distal nodes; peduncle 0.9–2.2 mm. |
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Euphorbia alta |
Euphorbia ocellata |
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Phenology | Flowering and fruiting summer. | |||||
Habitat | Montane pine-oak and mixed conifer forests, disturbed roadsides, logged areas. | |||||
Elevation | 1500–3000 m. (4900–9800 ft.) | |||||
Distribution |
AZ; NM; Mexico
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AZ; CA; ID; NV; UT
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Discussion | Euphorbia alta is a montane species from southern Arizona, New Mexico, and northern and central Mexico that is very similar to and sometimes difficult to distinguish from E. spathulata. Euphorbia alta tends to be a robust biennial, whereas E. spathulata is strictly annual. The most consistent characteristic to separate these two species is that the ovaries and capsules of E. alta are distinctly papillate, with the papillae rising sharply above the surface, whereas the ovaries and capsules of E. spathulata are merely verrucose, with the protuberances lower and rounded. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 279. | ||||
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Tithymalus altus | Chamaesyce ocellata | ||||
Name authority | Norton: N. Amer. Euphorbia, 24, plate 24. (1899) | Durand & Hilgard: Pl. Heermann., 46. (1854) | ||||
Web links |