Euphorbia lurida |
Euphorbia curtisii |
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woodland spurge |
Curtis' spurge, Sandhills spurge |
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Habit | Herbs, perennial, with thick rootstock. | Herbs, perennial, with spreading rootstock. |
Stems | erect or ascending, unbranched, sometimes sinuous, 5–30 cm, glabrous or sparsely to densely puberulent. |
erect or ascending, branched, solitary or few, previous year's dead stems not persistent, 20–40 cm, usually glabrous, rarely strigose to sericeous at nodes. |
Leaves | 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. |
alternate; stipules to 0.1 mm; petiole to (0–)1–2 mm, glabrous or strigose to sericeous; blade usually linear, occasionally elliptic, rarely ovate, proximal often greatly reduced and often scalelike, 10–30 × 1.5–6 mm, base cuneate, margins entire, occasionally sparsely ciliate, apex rounded or broadly acute, abaxial surface glabrous or sparsely strigose to sericeous, adaxial surface glabrous; venation obscure, only midvein conspicuous. |
Involucre | 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. |
campanulate, 1–1.2 × 1.3–1.5(–1.7) mm, glabrous or strigose to sericeous on distal 1/2; glands 5, green, reniform, 0.3 × 0.6 mm; appendages white, semicircular, 0.3–0.4 × 0.6–0.8 mm, entire. |
Staminate flowers | 10–20. |
20–25. |
Pistillate flowers | ovary glabrous or puberulent; styles 0.7–1 mm, 2-fid. |
ovary glabrous or sparsely strigose to sericeous; styles 0.6–1.1 mm, 2-fid at apex to 1/2 length. |
Capsules | ovoid, 3.5–4 × 4–4.5 mm, 3-lobed; cocci rounded, smooth to slightly rugose, glabrous; columella 3.2–3.5 mm. |
globose, 2.5–3.2 × 4.3–5.1 mm, glabrous or sparsely strigose to sericeous; columella 2.4–3.1 mm. |
Seeds | 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. |
usually gray to black, occasionally brown, ovoid-globose, 2.2 × 1.8 mm, smooth; caruncle absent. |
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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Cyathia | peduncle 0.3–0.9 mm. |
in terminal pleiochasia (fertile axillary branches occasionally present); peduncle 6.5–17 mm, filiform, glabrous. |
Euphorbia lurida |
Euphorbia curtisii |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting early spring–summer. |
Habitat | Open pine-oak forests, dry slopes and canyons. | Xeric to dry oak or oak-pine scrub of sand hills, pine-oak woodlands, pine-oak savannas. |
Elevation | 1300–2800 m. (4300–9200 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
AZ; CA; NM; NV; UT; Mexico (Baja California)
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FL; GA; NC; SC
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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.) |
Euphorbia curtisii is found in the Gulf and Atlantic coastal plains. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 305. | FNA vol. 12, p. 245. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | E. palmeri, E. palmeri var. subpubens, E. subpubens, Tithymalus luridus, T. palmeri, T. subpubens | E. eriogonoides, Tithymalopsis curtisii, T. eriogonoides |
Name authority | Engelmann: in J. C. Ives, Rep. Colorado R. 4: 26. (1861) | Engelmann ex Chapman: Fl. South. U.S., 401. (1860) |
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