Euphorbia radians |
Euphorbia rayturneri |
|
---|---|---|
sun spurge |
|
|
Habit | Herbs, perennial, with moniliform tuberous rootstock. | Herbs, annual, with slender taproot. |
Stems | erect, 5–20(–30) cm, usually glabrous, occasionally puberulent; branches ± straight. |
prostrate, 4–8 cm, uniformly strigillose. |
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. |
opposite; stipules distinct, filiform, 0.6–0.9 mm, pilose; petiole 0.5–0.9 mm, strigillose; blade ovate to elliptic, often slightly falcate, 5–11 × 2–5 mm, base asymmetric, one side cordate, other round to attenuate, margins sharply serrulate, apex acute, surfaces often with red spot toward middle, abaxial surface strigillose, adaxial surface glabrescent; only midvein conspicuous. |
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. |
obconic, 0.9–1.2 × 0.8–1.2 mm, strigillose; glands 4, green, yellow, or light pink, circular to oblong, 0.2 × 0.2–0.3 mm; appendages absent or green, yellow, or light pink, forming narrow margin on distal portion of gland, 0–0.1 × 0.2–0.3 mm, distal margin entire. |
Staminate flowers | 20–25. |
5–8. |
Pistillate flowers | ovary glabrous or puberulent, styles 3–4 mm, 2-fid 1/2 to nearly entire length. |
ovary strigillose-canescent; styles 0.3–0.4 mm, unbranched. |
Capsules | depressed-globose, 3.8–5 × 4–5 mm, 3-lobed, glabrous or puberulent; columella 3.6–4.5 mm. |
oblate, 1.7–2 × 2.2–2.7 mm, strigillose; columella 1.5–1.9 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. |
blackish brown, broadly ovoid, 3-angled in cross section, 1.2–1.4 × 1–1.1 mm, with 2 well-defined transverse ridges that do not pass through abaxial keel. |
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. |
|
Cyathia | peduncle 2–5.5 mm. |
solitary at distal nodes; peduncle 0.5–1.6 mm. |
2n | = 14. |
|
Euphorbia radians |
Euphorbia rayturneri |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting late summer–early fall. |
Habitat | Pinyon-juniper woodlands, oak savannas, desert grasslands and scrub. | Desert grasslands. |
Elevation | 700–2500 m. (2300–8200 ft.) | 1400–1700 m. (4600–5600 ft.) |
Distribution |
AZ; TX; Mexico
|
NM |
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 rayturneri is known from only three collections in extreme southwestern New Mexico. Given its close proximity to the Mexican border, the species may also occur in the adjacent states of Chihuahua or Sonora. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 324. | FNA vol. 12, p. 286. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Poinsettia radians | |
Name authority | Bentham: Pl. Hartw., 8. (1839) | V. W. Steinmann & Jercinovic: Novon 22: 482, figs. 1, 2. (2013) |
Web links |