Euphorbia abramsiana |
Euphorbia rayturneri |
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Abrams' sandmat, Abrams' spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, annual, with slender taproot. |
Stems | prostrate, mat-forming, 10–35(–50) cm, shortly pilose or puberulent at least proximally, often glabrous distally. |
prostrate, 4–8 cm, uniformly strigillose. |
Leaves | opposite; stipules distinct, divided into 5–7 subulate-filiform segments, 0.6–1.1 mm, usually glabrous, rarely pilose; petiole 0.5–1 mm, glabrous; blade ovate, elliptic-oblong, or slightly ovate-cordate, 3–11 × 2–5 mm, base asymmetric, truncate to hemicordate, margins serrulate at least toward apex, often entire toward base, apex acute to obtuse, surfaces sometimes with red spot in center, glabrous; usually only the midvein conspicuous. |
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 | obconic, 0.5–0.6 × 0.4–0.5 mm, glabrous; glands 4, yellowish to pink, circular to oblong, 0.1 × 0.1–0.2 mm; appendages absent, or white to pink, semicircular to broadly ovate, to 0.1 × 0.2 mm, distal margin entire or shallowly lobed. |
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 | 3–5. |
5–8. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid nearly entire length. |
ovary strigillose-canescent; styles 0.3–0.4 mm, unbranched. |
Capsules | ellipsoid to ovoid, 1.3–1.5 × 1.1–1.5 mm, glabrous; columella 1–1.3 mm. |
oblate, 1.7–2 × 2.2–2.7 mm, strigillose; columella 1.5–1.9 mm. |
Seeds | light gray to light brown, narrowly ovoid to ovoid, 4-angled in cross section, 1–1.2 × 0.6–0.7 mm, with 3–5 prominent transverse ridges that often interrupt abaxial keel. |
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. |
Cyathia | solitary at distal nodes of primary stems or at nodes of short congested axillary branchlets; peduncle 0.2–0.5 mm. |
solitary at distal nodes; peduncle 0.5–1.6 mm. |
2n | = 14. |
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Euphorbia abramsiana |
Euphorbia rayturneri |
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Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting late summer–early fall. |
Habitat | Desert scrub and desert grasslands. | Desert grasslands. |
Elevation | -40–1400 m. (-100–4600 ft.) | 1400–1700 m. (4600–5600 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Sonora)
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NM |
Discussion | 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.) |
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Source | FNA vol. 12, p. 259. | FNA vol. 12, p. 286. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce abramsiana | |
Name authority | L. C. Wheeler: Bull. S. Calif. Acad. Sci. 33: 109. (1934) | V. W. Steinmann & Jercinovic: Novon 22: 482, figs. 1, 2. (2013) |
Web links |