Euphorbia abramsiana |
Euphorbia lurida |
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Abrams' sandmat, Abrams' spurge |
woodland spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, perennial, with thick rootstock. |
Stems | prostrate, mat-forming, 10–35(–50) cm, shortly pilose or puberulent at least proximally, often glabrous distally. |
erect or ascending, unbranched, sometimes sinuous, 5–30 cm, glabrous or sparsely to densely puberulent. |
Leaves | opposite; stipules distinct, divided into 5–7 subulate-filiform segments, 0.6–1.1 mm, usually glabrous, rarely pilose; petiole 0.5–1 mm, glabrous; blade ovate, elliptic-oblong, or slightly ovate-cordate, 3–11 × 2–5 mm, base asymmetric, truncate to hemicordate, margins serrulate at least toward apex, often entire toward base, apex acute to obtuse, surfaces sometimes with red spot in center, glabrous; usually only the midvein conspicuous. |
petiole 0–1 mm; blade oblanceolate to obovate, 8–20 mm × 3–7 mm, base truncate or cuneate, margins entire, apex obtuse to rounded, minutely mucronate, surfaces puberulent or glabrous; venation inconspicuous, only midvein prominent. |
Involucre | obconic, 0.5–0.6 × 0.4–0.5 mm, glabrous; glands 4, yellowish to pink, circular to oblong, 0.1 × 0.1–0.2 mm; appendages absent, or white to pink, semicircular to broadly ovate, to 0.1 × 0.2 mm, distal margin entire or shallowly lobed. |
cupulate, 2–2.2 × 1.3–1.8 mm, glabrous; glands 4, oblong to broadly ovate, usually truncate, 0.5–0.8 × 1–1.6 mm, margins irregularly crenate to strongly dentate; horns absent or usually divergent or straight, 0.1–0.3 mm, usually slightly longer than, occasionally equaling, teeth on gland margin. |
Staminate flowers | 3–5. |
10–20. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid nearly entire length. |
ovary glabrous or puberulent; styles 0.7–1 mm, 2-fid. |
Capsules | ellipsoid to ovoid, 1.3–1.5 × 1.1–1.5 mm, glabrous; columella 1–1.3 mm. |
ovoid, 3.5–4 × 4–4.5 mm, 3-lobed; cocci rounded, smooth to slightly rugose, glabrous; columella 3.2–3.5 mm. |
Seeds | light gray to light brown, narrowly ovoid to ovoid, 4-angled in cross section, 1–1.2 × 0.6–0.7 mm, with 3–5 prominent transverse ridges that often interrupt abaxial keel. |
gray to dark gray, truncate-oblong to truncate-ovoid, 2.8–3 × 1.7–2 mm, irregularly pitted; caruncle conic, 0.6 × 0.7 mm. |
Cyathia | solitary at distal nodes of primary stems or at nodes of short congested axillary branchlets; peduncle 0.2–0.5 mm. |
peduncle 0.3–0.9 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3–5, each 1–4 times 2-branched; pleiochasial bracts ovate to broadly ovate or oblanceolate, wider than distal leaves; dichasial bracts distinct, rounded, oblanceolate, or subreniform, base cuneate or obtuse, margins entire, apex obtuse, slightly mucronate; axillary cymose branches 0–4. |
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Euphorbia abramsiana |
Euphorbia lurida |
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Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting spring–summer. |
Habitat | Desert scrub and desert grasslands. | Open pine-oak forests, dry slopes and canyons. |
Elevation | -40–1400 m. (-100–4600 ft.) | 1300–2800 m. (4300–9200 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Sonora)
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AZ; CA; NM; NV; UT; Mexico (Baja California)
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Discussion | Euphorbia lurida has been treated as a complex of several taxa in the past, but only a single, broadly-defined species is recognized here. This species is variable in both the pubescence and shape of the bracts subtending the cyathia and also in the degree of crenation of the gland margin. In the northern part of its range, E. lurida appears to intergrade with E. brachycera, and it can be difficult to distinguish these two species in northern Arizona and New Mexico. A report of the species from Sonora, Mexico, based on a single immature collection (V. W. Steinmann and R. S. Felger 1997) has not been verified. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 259. | FNA vol. 12, p. 305. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Chamaesyce abramsiana | E. palmeri, E. palmeri var. subpubens, E. subpubens, Tithymalus luridus, T. palmeri, T. subpubens |
Name authority | L. C. Wheeler: Bull. S. Calif. Acad. Sci. 33: 109. (1934) | Engelmann: in J. C. Ives, Rep. Colorado R. 4: 26. (1861) |
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