Euphorbia radians |
Euphorbia peplidion |
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sun spurge |
low spurge |
|
Habit | Herbs, perennial, with moniliform tuberous rootstock. | Herbs, annual, with taproot. |
Stems | erect, 5–20(–30) cm, usually glabrous, occasionally puberulent; branches ± straight. |
erect, unbranched or branched, 5–20 cm, glabrous. |
Leaves | alternate; petiole 0–2 mm, glabrous or strigose; blade linear-lanceolate to ovate or broadly elliptic, 25–50 × 3–20 mm, unlobed, base rounded (tapered to petiole), margins with few glandular teeth, strigillose, flat to revolute, apex acute, abaxial surface coarsely strigose, adaxial surface strigose-hirsute; venation pinnate, midvein prominent. |
petiole 0–0.2 mm; blade linear-oblanceolate to cuneate-spatulate, 5–20 × 1–4 mm, base attenuate, margins entire, apex rounded to obtuse, surfaces glabrous; venation inconspicuously pinnate, midvein prominent. |
Involucre | broadly globose-cupulate, 1.7–2.1 × 2.2–2.5 mm, glabrous or puberulent; involucral lobes divided into triangular segments; glands 1–4(–5), white, sessile and broadly attached, 1.1 × 1.4 mm, opening oblong, glabrous; appendages absent. |
broadly campanulate-turbinate, 0.8–1 × 0.6–0.9 mm, glabrous; glands 4, elliptic, 0.2–0.3 × 0.5–0.6 mm; horns divergent, 0.4–0.5 mm. |
Staminate flowers | 20–25. |
5–10. |
Pistillate flowers | ovary glabrous or puberulent, styles 3–4 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous; styles 0.5–0.7 mm, 2-fid. |
Capsules | depressed-globose, 3.8–5 × 4–5 mm, 3-lobed, glabrous or puberulent; columella 3.6–4.5 mm. |
depressed-globose, 1.8–2.3 × 2.6–3 mm, 3-lobed; cocci slightly flattened, without wings, smooth, glabrous; columella 1.3–1.5 mm. |
Seeds | white, mottled brown to gray, ellipsoid, rounded in cross section, 4–4.6 × 2.4–3.2 mm, smoothly and broadly pitted or grooved; caruncle 0.1 mm. |
gray to brown, oblong, 1.3–1.6 × 0.9–1.1 mm, abaxial faces irregularly large-pitted, adaxial faces longitudinally sulcate; caruncle flat, umbonate, 2-lobed, 0.4 × 0.7 mm. |
Cyathial | arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched (often highly condensed); pleiochasial bracts 6–8(–10), as tight involucrate whorl, wholly white to pale pink or red, usually narrower than distal leaves; dichasial bracts linear and highly reduced. |
arrangement: terminal pleiochasial branches 3(–5), 1–3 times 2-branched; pleiochasial bracts linear, lanceolate, or spatulate, similar in size to distal leaves; dichasial bracts distinct, rhomboid-lanceolate to ovate, falcate, base rounded to obtuse, margins entire or slightly erose, apex acute; axillary cymose branches 0–3. |
Cyathia | peduncle 2–5.5 mm. |
peduncle 0.3–0.5 mm. |
Euphorbia radians |
Euphorbia peplidion |
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Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting late winter–spring. |
Habitat | Pinyon-juniper woodlands, oak savannas, desert grasslands and scrub. | Dry, sandy areas, open areas with poor soils, roadsides, stream banks. |
Elevation | 700–2500 m. (2300–8200 ft.) | 100–300 m. (300–1000 ft.) |
Distribution |
AZ; TX; Mexico
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TX |
Discussion | Euphorbia radians is widely distributed but scattered from the Sonoran and Chihuahuan deserts south to Oaxaca in Mexico. The species is distinct among species in sect. Poinsettia in the flora area in its precocious habit, often flowering before the leaves emerge. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia peplidion is native to central and south-central Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 324. | FNA vol. 12, p. 306. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Poinsettia radians | Tithymalus peplidion |
Name authority | Bentham: Pl. Hartw., 8. (1839) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 191. (1859) |
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