Euphorbia abramsiana |
Euphorbia graminea |
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Abrams' sandmat, Abrams' spurge |
grassleaf spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, usually annual, rarely perennial, with slender, rarely tuberous, taproot. |
Stems | prostrate, mat-forming, 10–35(–50) cm, shortly pilose or puberulent at least proximally, often glabrous distally. |
erect or ascending, branched, 30–80(–110) cm, strigillose or glabrescent, sharply angled. |
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. |
usually alternate, sometimes some opposite; stipules usually 0.2–0.5 mm, rarely rudimentary; petiole 0.4–5.9 mm, strigillose; blade ovate, elliptic, linear-elliptic, or oblong, 10–83 × 3–39 mm, base attenuate, rounded, or cuneate, margins entire, apex acute or obtuse, surfaces strigillose; venation occasionally obscure on narrow leaves, 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. |
campanulate or obconic, 1–1.8 × 0.8–1.7 mm, glabrous or strigillose toward rim; glands (1–)2–4, yellow to greenish, elliptic or oblong, 0.1–0.3 × 0.2–0.4 mm; appendages white to tinged purple, ovate and often hoodlike or forming narrow rim around distal margin of gland, 0.3–1.6 × 0.4–0.9 mm, entire. |
Staminate flowers | 3–5. |
30–40. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.7–1 mm, 2-fid from 1/2 to nearly entire length. |
Capsules | ellipsoid to ovoid, 1.3–1.5 × 1.1–1.5 mm, glabrous; columella 1–1.3 mm. |
ovoid-oblate, 2.5–3 × 3–3.5 mm, glabrous; columella 1.6–1.9 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. |
gray, brown, or nearly black, ovoid, circular or weakly angled in cross section, 1.5–1.7 × 1.3–1.5 mm, coarsely tuberculate with longitudinal rows of shallow pits; caruncle absent or punctiform, 0.1–0.2 mm. |
Cyathia | solitary at distal nodes of primary stems or at nodes of short congested axillary branchlets; peduncle 0.2–0.5 mm. |
in usually terminal, rarely axillary, dichasia, distal dichasial bracts often white; peduncle 0.4–4.5 mm (to 15 mm at first node of inflorescence), glabrous. |
Euphorbia abramsiana |
Euphorbia graminea |
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Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting year-round. |
Habitat | Desert scrub and desert grasslands. | Disturbed, weedy, or urban areas. |
Elevation | -40–1400 m. (-100–4600 ft.) | 0–500 m. (0–1600 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Sonora)
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AR; CA; FL; LA; TX; Mexico; Central America; South America [Introduced in North America; introduced also in West Indies, Asia, Pacific Islands]
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Discussion | Euphorbia graminea occurs natively from northern South America to northern Mexico. The species is a variable and taxonomically complex entity whose boundaries are not well defined and are in need of further study. Euphorbia graminea is often weedy and has recently become established in warmer areas of the southern United States, where it will likely become more common in the future. In recent years, a cultivar of E. graminea has found considerable horticultural success and is marketed under the trade name "Diamond Frost." (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 259. | FNA vol. 12, p. 246. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Chamaesyce abramsiana | |
Name authority | L. C. Wheeler: Bull. S. Calif. Acad. Sci. 33: 109. (1934) | Jacquin: Select. Stirp. Amer. Hist., 151. (1763) |
Web links |