Euphorbia cordifolia |
Euphorbia rayturneri |
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heartleaf sandmat |
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Habit | Herbs, annual, with taproot. | Herbs, annual, with slender taproot. |
Stems | prostrate, occasionally mat-forming, 10–43 cm, glabrous. |
prostrate, 4–8 cm, uniformly strigillose. |
Leaves | opposite; stipules usually distinct, occasionally connate at base, filiform, 1–1.2(–2.8) mm, usually glabrous, rarely pilose; petiole 0.4–1 mm, usually glabrous; blade ovate to oblong, 4.4–12 × 2.6–7.6 mm, base asymmetric, cordate to rounded, margins entire, apex rounded to mucronulate, surfaces glabrous; only 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 | campanulate, 1–1.3 × 1–1.3 mm, glabrous; glands 4, yellowish to pink, elliptic, 0.3–0.5 × 0.5–1 mm; appendages whitish to pink, sometimes drying red, elliptic to ovoid, 1.1–1.5 × 1.2–1.9 mm, distal margin entire, retuse, or erose. |
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 | 5–40. |
5–8. |
Pistillate flowers | ovary glabrous; styles 0.5–0.8 mm, 2-fid nearly entire length. |
ovary strigillose-canescent; styles 0.3–0.4 mm, unbranched. |
Capsules | ovoid, 2–3 mm diam., glabrous; columella 1.2–2.7 mm. |
oblate, 1.7–2 × 2.2–2.7 mm, strigillose; columella 1.5–1.9 mm. |
Seeds | gray or tan with dark brown mottling, ovoid, bluntly 3–4-angled in cross section, 1.8–2.1 × 1.2–1.4 mm, smooth to rugose. |
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; peduncle 0.9–3 mm. |
solitary at distal nodes; peduncle 0.5–1.6 mm. |
2n | = 14. |
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Euphorbia cordifolia |
Euphorbia rayturneri |
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Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting late summer–early fall. |
Habitat | Xeric oak-pine scrub, pine-barrens, sand barrens, sandy stream banks. | Desert grasslands. |
Elevation | 0–200 m. (0–700 ft.) | 1400–1700 m. (4600–5600 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; OK; SC; TX
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NM |
Discussion | Euphorbia cordifolia is easily identified by its cordate to rounded leaf base and distinctive filiform stipules. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 12, p. 265. | FNA vol. 12, p. 286. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce cordifolia | |
Name authority | Elliott: Sketch. Bot. S. Carolina 2: 656. (1824) | V. W. Steinmann & Jercinovic: Novon 22: 482, figs. 1, 2. (2013) |
Web links |