Euphorbia albomarginata |
Euphorbia blodgettii |
|
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rattlesnake sandmat, rattlesnake weed, white-margin sandmat or sandwort, whitemargin sandmat |
limestone sandmat |
|
Habit | Herbs, perennial, with moderately to strongly thickened rootstock. | Herbs, usually annual, occasionally perennial, with slender to slightly thickened taproot, 3.5 mm diam.. |
Stems | prostrate, occasionally mat-forming, frequently rooting at nodes, 10–80 cm, glabrous. |
prostrate to decumbent, loosely mat-forming, often rooting at nodes, 10–45 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. |
opposite; stipules distinct, subulate filiform segments (lower side), or connate forming conspicuous, broad deltate scale (upper side), toothed, 0.5–1 mm, glabrous; petiole 0.7–1 mm, glabrous; blade ovate to oblong-elliptic, 4–10 × 2–5 mm, base asymmetric, subcordate to rounded, margins usually entire, occasionally toothed, apex usually obtuse to rounded, occasionally acute to apiculate, surfaces without red blotch, glabrous; 3-veined from base, 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. |
turbinate to campanulate, 0.5–0.6 × 0.4–0.6 mm, glabrous; glands 4, red, slightly concave, elliptic-oblong, 0.1 × 0.1–0.3 mm; appendages white to pink, unequal, pair near sinus lunate to oblong, 0.1–0.2 × 0.1–0.3 mm, distal margin entire, crenulate, or irregularly sinuate, other pair sometimes rudimentary, 0–0.1 × 0.1–0.3 mm, distal margin crenulate or entire. |
Staminate flowers | 15–30. |
8–12. |
Pistillate flowers | ovary glabrous; styles 0.3–0.7 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
Capsules | broadly ovoid, 1.1–2.3 × 1.2–2 mm, glabrous; columella 1.1–1.6 mm. |
broadly ovoid, 1.2–1.7 × 1.4–1.9 mm, glabrous; columella 1.2–1.6 mm. |
Seeds | white to gray or brownish red, oblong-ovoid, 4-angled in cross section, 1–1.7 × 0.5–0.8 mm, smooth. |
gray to reddish brown, oblong-ovoid, 4-angled in cross section, 0.9–1.1 × 0.5–0.6 mm, flat or obscurely wrinkled. |
Cyathia | solitary at distal nodes; peduncle 1–4 mm. |
solitary or in small, cymose clusters at distal nodes of stem or on congested, axillary branches; peduncle 0.4–0.6 mm. |
Euphorbia albomarginata |
Euphorbia blodgettii |
|
Phenology | Flowering and fruiting year-round. | Flowering and fruiting year-round. |
Habitat | Disturbed areas in desert scrub, grasslands, mesquite woodlands, chaparral. | Coastal sand dunes and disturbed upland sandy areas. |
Elevation | 0–2300 m. (0–7500 ft.) | 0–20 m. (0–100 ft.) |
Distribution |
AZ; CA; CO; NM; NV; OK; TX; UT; Mexico [Introduced in Pacific Islands (Hawaii)]
|
FL |
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.) |
Euphorbia blodgettii is found only in peninsular Florida. It is closely related to E. garberi, E. porteriana, and E. serpens (Y. Yang and P. E. Berry 2011). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 259. | FNA vol. 12, p. 261. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce albomarginata | Chamaesyce blodgettii, C. nashii |
Name authority | Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 2(4): 174. (1857) | Engelmann ex Hitchcock: Rep. (Annual) Missouri Bot. Gard. 4: 126, plate 13. (1893) |
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