Euphorbia serrula |
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sawtooth sandmat |
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Habit | Herbs, annual, with slender taproot. |
Stems | prostrate or ascending, 5–20 cm, usually pilose to villous, rarely glabrate. |
Leaves | opposite; stipules usually distinct, rarely connate at base, triangular or laciniate into subulate segments, 1–1.8 mm, glabrous; petiole 0.3–0.8 mm, glabrous or villous; blade oblong, ovate, or elliptic, sometimes falcate, 3–11 × 2–5 mm, base asymmetric, rounded to hemicordate, margins sharply serrate to serrulate, usually with conspicuous teeth at base of leaf, apex usually obtuse, rarely acute, surfaces frequently with red blotch in center, not papillate, sparsely pilose to glabrate; only midvein conspicuous. |
Involucre | obconic, 0.8–1.1 × 0.8–1 mm, glabrous; glands 4, greenish yellow, usually reniform to elliptic, rarely circular, 0.1 × 0.1–0.2 mm; appendages usually white, rarely light pink, orbiculate, 0.1–0.3 × 0.2–0.4 mm, distal margin entire or crenulate. |
Staminate flowers | 7–15. |
Pistillate flowers | ovary glabrous; styles 0.3–0.5 mm, 2-fid 1/2 length. |
Capsules | oblate, cocci not elongated nor terminating in empty portion, 2–2.6 × 3.2–3.7 mm, glabrous; columella 1.7–2.1 mm. |
Seeds | white to light brown, broadly ellipsoid to ovoid, 3–4-angled in cross section, 1.5–1.8 × 1.1–1.3(–1.5) mm, smooth to minutely rugulose or with scattered small depressions. |
Cyathia | solitary at distal nodes; peduncle 0.4–1.8(–2.3) mm. |
Euphorbia serrula |
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Phenology | Flowering and fruiting spring–fall. |
Habitat | Desert scrub, with creosote bush, grasslands with mesquite and yucca, rarely in ponderosa pine woodlands, often sandy substrates. |
Elevation | 300–1900 m. (1000–6200 ft.) |
Distribution |
AZ; NM; TX; Mexico
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Discussion | In Mexico, Euphorbia serrula is found from Chihuahua and Coahuila south to Puebla. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 288. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | |
Synonyms | Chamaesyce serrula |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 188. (1859) |
Web links |