Euphorbia albomarginata |
Euphorbia floridana |
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rattlesnake sandmat, rattlesnake weed, white-margin sandmat or sandwort, whitemargin sandmat |
greater Florida spurge |
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Habit | Herbs, perennial, with moderately to strongly thickened rootstock. | Herbs, perennial, with slender to moderately thickened rootstock. |
Stems | prostrate, occasionally mat-forming, frequently rooting at nodes, 10–80 cm, glabrous. |
erect, 20–65 cm. |
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. |
petiole absent; blade linear to linear-elliptic or linear-lanceolate, 30–105 × 2–4(–7) mm, chartaceous, base attenuate, rounded, or nearly truncate, apex acute; only midvein evident. |
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. |
campanulate or obconic, 1.6–3.3 × 1.8–3.1 mm, lobes ovate, 0.5–0.7 mm, ciliate, exceeded by glands; glands yellow-green, oblong to trapezoidal, 0.5–0.8 × 0.8–1.2 mm, distal margins deeply erose. |
Staminate flowers | 15–30. |
20. |
Pistillate flowers | ovary glabrous; styles 0.3–0.7 mm, 2-fid nearly entire length. |
gynophore exserted 2.9–5.3 mm, calyxlike lobes triangular, 0.3–0.7 mm; styles connate 1/3–1/4 length, 1.1–1.7 mm. |
Capsules | broadly ovoid, 1.1–2.3 × 1.2–2 mm, glabrous; columella 1.1–1.6 mm. |
oblate-ovoid, 4.6–5.5 × 8.9–9 mm, strongly 3-lobed; columella 3.4–4.2 mm. |
Seeds | white to gray or brownish red, oblong-ovoid, 4-angled in cross section, 1–1.7 × 0.5–0.8 mm, smooth. |
brown to blackish, depressed-globose, circular in cross section, 2.8–3 × 3.2–3.6 mm, smooth, base flattened, with punctiform depressions, apex flattened. |
Cyathia | solitary at distal nodes; peduncle 1–4 mm. |
peduncle (except for that of 1st cyathium at base of pleiochasia) 2–5 mm (not exceeding dichasial bracts). |
Cyathial | arrangement: terminal pleiochasial branches 3–5, 3–16 cm, 3–5(–7) times 2-branched; pleiochasial bracts linear-lanceolate or narrowly ovate, 19–55 × 4–12 mm, margins entire, apex acute or acuminate; dichasial bracts usually ovate, lanceolate, or oblong, rarely deltate, 8–21 × 4–14 mm, margins entire, apex acute, acuminate, or rounded with mucronate tip; axillary cymose branches 1–3(–6). |
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Euphorbia albomarginata |
Euphorbia floridana |
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Phenology | Flowering and fruiting year-round. | Flowering and fruiting spring–fall. |
Habitat | Disturbed areas in desert scrub, grasslands, mesquite woodlands, chaparral. | Xeric pine-oak sandhills, pine scrub, sandy soils. |
Elevation | 0–2300 m. (0–7500 ft.) | 20–80 m. (100–300 ft.) |
Distribution |
AZ; CA; CO; NM; NV; OK; TX; UT; Mexico [Introduced in Pacific Islands (Hawaii)]
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AL; FL; GA
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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.) |
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Source | FNA vol. 12, p. 259. | FNA vol. 12, p. 314. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Nummulariopsis |
Sibling taxa | ||
Synonyms | Chamaesyce albomarginata | Galarhoeus floridanus |
Name authority | Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 2(4): 174. (1857) | Chapman: Fl. South. U.S., 401. (1860) |
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