Euphorbia lurida |
Euphorbia lata |
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woodland spurge |
broadleaf spurge, hoary sandmat |
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Habit | Herbs, perennial, with thick rootstock. | Herbs, perennial, with moderately thickened to robust rootstock. |
Stems | erect or ascending, unbranched, sometimes sinuous, 5–30 cm, glabrous or sparsely to densely puberulent. |
ascending to erect, or prostrate, 10–25 cm, strigose to short-sericeous or ± villous. |
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. |
opposite; stipules distinct, filiform, 0.8–1.3 mm, strigose to short-sericeous or ± villous; petiole 0.5–2 mm, densely strigose to short-sericeous or ± villous; blade narrowly to broadly ovate-deltate, older ones often falcate, 4–12 × 3–7 mm, base asymmetric, obliquely rounded to obtuse, noticeably wider on one side, margins entire, often ± revolute, apex broadly acute, surfaces strigose to short-sericeous or ± villous; obscurely 3–5-veined from base, midvein prominent abaxially. |
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. |
broadly campanulate, 2–2.5 × 2.2–2.6, strigose; glands 4, greenish, oblong to semilunate, 0.2–0.7 × 0.6–1 mm; appendages rudimentary or white, forming narrow band, (0–)0.1–0.2 × (0–)0.6–1 mm, distal margin entire or crenate. |
Staminate flowers | 10–20. |
25–35. |
Pistillate flowers | ovary glabrous or puberulent; styles 0.7–1 mm, 2-fid. |
ovary densely strigose to short-sericeous or ± villous; styles dark purplish, 0.8–1.2 mm, 2-fid 1/2 to nearly entire 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. |
ovoid, 1.9–2.3 × 2–2.4 mm, strigose to short-sericeous or ± villous; columella 1.7–2.2 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. |
whitish, oblong, 4-angled in cross section, faces concave, 1.5–1.8(–2) × 0.6–0.9 mm, smooth. |
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. |
solitary at distal nodes; peduncle 1–3 mm. |
2n | = 28, 56. |
|
Euphorbia lurida |
Euphorbia lata |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring–fall. |
Habitat | Open pine-oak forests, dry slopes and canyons. | Mountain slopes, canyons, basins, rocky prairies, roadsides, disturbed sites, usually in calcareous soils, sometimes in igneous-derived, sandy or rocky soils. |
Elevation | 1300–2800 m. (4300–9200 ft.) | 600–2200 m. (2000–7200 ft.) |
Distribution |
AZ; CA; NM; NV; UT; Mexico (Baja California)
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CO; KS; NM; OK; TX; Mexico (Chihuahua, Coahuila)
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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. 305. | FNA vol. 12, p. 275. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | E. palmeri, E. palmeri var. subpubens, E. subpubens, Tithymalus luridus, T. palmeri, T. subpubens | E. dilatata, Chamaesyce lata, E. rinconis |
Name authority | Engelmann: in J. C. Ives, Rep. Colorado R. 4: 26. (1861) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 188. (1859) |
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