Euphorbia albomarginata |
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rattlesnake sandmat, rattlesnake weed, white-margin sandmat or sandwort, whitemargin sandmat |
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Habit | Herbs, perennial, with moderately to strongly thickened rootstock. |
Stems | prostrate, occasionally mat-forming, frequently rooting at nodes, 10–80 cm, glabrous. |
Leaves | opposite; stipules connate into conspicuous, deltate or ovate scale, white, 0.4–1(–2) mm, glabrous; petiole less than 1 mm, glabrous; blade ovate, oblong or orbiculate, 3–8(–15) × 3–7 mm, base strongly asymmetric, obtuse to hemicordate, margins whitish, entire, apex obtuse, rarely mucronulate, surfaces often with red blotch in center, glabrous; 3-veined from base but usually only midvein conspicuous. |
Involucre | campanulate, 0.8–1.1 × 0.9–2 mm, glabrous; glands 4, greenish yellow to red, usually oblong to reniform, rarely subcircular, 0.2–0.5 × (0.2–)0.3–0.8 mm; appendages white to pink, flabellate to oblong, 0.3–1 × 0.6–1.3 mm, distal margin entire or crenulate to erose. |
Staminate flowers | 15–30. |
Pistillate flowers | ovary glabrous; styles 0.3–0.7 mm, 2-fid nearly entire length. |
Capsules | broadly ovoid, 1.1–2.3 × 1.2–2 mm, glabrous; columella 1.1–1.6 mm. |
Seeds | white to gray or brownish red, oblong-ovoid, 4-angled in cross section, 1–1.7 × 0.5–0.8 mm, smooth. |
Cyathia | solitary at distal nodes; peduncle 1–4 mm. |
Euphorbia albomarginata |
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Phenology | Flowering and fruiting year-round. |
Habitat | Disturbed areas in desert scrub, grasslands, mesquite woodlands, chaparral. |
Elevation | 0–2300 m. (0–7500 ft.) |
Distribution |
AZ; CA; CO; NM; NV; OK; TX; UT; Mexico [Introduced in Pacific Islands (Hawaii)]
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Discussion | Euphorbia albomarginata is native to northern and central Mexico and the southwestern and south-central United States. The species occurs in a variety of habitats in western North America and in some areas is quite weedy. It has been recorded as a waif in Louisiana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 259. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | |
Synonyms | Chamaesyce albomarginata |
Name authority | Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 2(4): 174. (1857) |
Web links |