Euphorbia alta |
Euphorbia astyla |
|
---|---|---|
giant spurge, roughpod spurge, tall spurge, warty spurge |
alkali spurge, Pecos spurge |
|
Habit | Herbs, annual or biennial, with taproot. | Herbs, perennial, with woody or fibrous-fleshy taproot, 5–12 mm thick. |
Stems | erect, branched, 20–60 cm, glabrous. |
decumbent, ascending, or erect, few to many emerging from woody crown, 5–25(–50) cm, glabrous. |
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 connate into deltate scale, 0.2–0.5 mm, minutely lacerate at apex, glabrous; petiole 0–0.2(–0.3) mm, glabrous; blade orbiculate-reniform to acute-cordate, 2–5(–8) × 2–5(–6) mm, base ± asymmetric, cordate to auriculate, sometimes clasping stem, margins entire, apex narrowly acute, surfaces glabrous; 2- or 3-veined from base, but usually only midvein conspicuous. |
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. |
broadly campanulate, 0.8–1.4 × 0.9–1.4 mm, glabrous; glands 4, yellow-green to brownish, oblong, 0.2–0.3 × 0.5–0.7 mm; appendages white, flabellate to oblong, 0.1–0.2(–0.5) × 0.4–0.8 mm, distal margin entire or dentate-crenate. |
Staminate flowers | 5–10. |
22–26. |
Pistillate flowers | ovary glabrous; styles 0.5–0.9 mm, 2-fid. |
ovary glabrous; styles 0.3–0.4 mm, unbranched, thickened-clavate. |
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. |
ovoid and broadly triangular, 1.5–1.9(–2.5) × 1.4–1.6(–2.2) mm, glabrous; columella 1.2–1.8 mm. |
Seeds | purple-black, ovoid, 1.6–2 × 1.3–1.7 mm, reticulate and areolate; caruncle reniform, flat, 0.5 × 0.7 mm. |
white, oblong, 4-angled in cross section, adaxial faces slightly concave, with long raphe between, 1.5–1.8 × 0.7–1 mm, markedly foveolate, with irregular to ± parallel or anastomosing ridges. |
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). |
|
Cyathia | peduncle 0.5–1 mm. |
solitary at distal nodes; peduncle 0.3–1(–1.5) mm. |
2n | = 28. |
|
Euphorbia alta |
Euphorbia astyla |
|
Phenology | Flowering and fruiting summer. | Flowering and fruiting late spring–early fall. |
Habitat | Montane pine-oak and mixed conifer forests, disturbed roadsides, logged areas. | Desert, grasslands, limestone substrates, usually on very saline or alkaline soils. |
Elevation | 1500–3000 m. (4900–9800 ft.) | 700–1100 m. (2300–3600 ft.) |
Distribution |
AZ; NM; Mexico
|
TX; Mexico (Coahuila, Nuevo León) |
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.) |
Euphorbia astyla is a specialist on halophytic, alkaline soils and is known in the flora area only in part of Pecos County. The species is closely related to E. jejuna but differs in its sessile or sub-sessile leaves with a cordate-auriculate base and involucral gland appendages that are not deeply lobed or cleft. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 261. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus altus | Chamaesyce astyla |
Name authority | Norton: N. Amer. Euphorbia, 24, plate 24. (1899) | Engelmann ex Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 40. (1862) |
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