Euphorbia glyptosperma |
Euphorbia curtisii |
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corrugate-seed spurge, rib-seed sandmat, ridge-seed spurge |
Curtis' spurge, Sandhills spurge |
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Habit | Herbs, annual, with taproot. | Herbs, perennial, with spreading rootstock. |
Stems | prostrate, loosely mat-forming, 5–40 cm, glabrous, sometimes slightly glaucous. |
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 | opposite; stipules usually distinct, linear-subulate, usually irregularly fringed or lobed, rarely laciniate, 0.4–2 mm, glabrous; petiole 0.2–2 mm, glabrous; blade narrowly oblong to oblong-obovate or oblong-ovate, 3–15 × 2–7 mm, base asymmetric, one side angled and other rounded to shallowly cordate, margins minutely sparsely serrulate, especially near apex and on longer side, apex rounded to obtuse, abaxial surface usually pale grayish green, adaxial surface sometimes reddish tinged or with reddish blotch, both surfaces glabrous; palmately veined at base, pinnate distally. |
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 | obconic, 0.6–0.9 × 0.3–0.6 mm, glabrous; glands 4, red to purple, narrowly oblong-elliptic, 0.1–0.2 × 0.1–0.5 mm; appendages white or pinkish tinged, semilunate and fringing distal margin of gland, 0.1–0.3 × 0.1–0.3 mm, distal margin usually irregularly crenulate or lobed. |
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 | 1–5. |
20–25. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid 1/2 length. |
ovary glabrous or sparsely strigose to sericeous; styles 0.6–1.1 mm, 2-fid at apex to 1/2 length. |
Capsules | broadly ovoid, 1.3–1.9 × 1.6–2 mm, glabrous; columella 1.3–1.5 mm. |
globose, 2.5–3.2 × 4.3–5.1 mm, glabrous or sparsely strigose to sericeous; columella 2.4–3.1 mm. |
Seeds | with thin white coat that readily falls off, surface below tan brown, oblong-ovoid, sharply angular in cross section, 1–1.4 × 0.6–0.9 mm, with 3–4(–6) prominent transverse ridges that usually interrupt abaxial keel. |
usually gray to black, occasionally brown, ovoid-globose, 2.2 × 1.8 mm, smooth; caruncle absent. |
Cyathia | solitary or in small, cymose clusters at distal nodes; peduncle 0.5–1.6 mm. |
in terminal pleiochasia (fertile axillary branches occasionally present); peduncle 6.5–17 mm, filiform, glabrous. |
2n | = 22. |
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Euphorbia glyptosperma |
Euphorbia curtisii |
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Phenology | Flowering and fruiting early summer–fall. | Flowering and fruiting early spring–summer. |
Habitat | Stream and river banks, sand prairies, loess hill prairies, meadows, ballast, open disturbed areas, roadsides. | Xeric to dry oak or oak-pine scrub of sand hills, pine-oak woodlands, pine-oak savannas. |
Elevation | 0–1800 m. (0–5900 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
AZ; CA; CO; CT; IA; ID; IL; IN; KS; LA; MA; ME; MI; MN; MO; MT; ND; NE; NH; NM; NV; NY; OK; OR; SD; TN; TX; UT; VT; WA; WI; WY; AB; BC; MB; NB; NS; ON; PE; QC; SK; Mexico (Chihuahua, Coahuila, Tamaulipas, Zacatecas)
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FL; GA; NC; SC
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Discussion | Euphorbia glyptosperma is one of the most widespread species of the genus in North America, and it is often quite weedy. It is likely native to much of the central United States, but in areas like eastern Canada, it occurs in highly disturbed habitats, and it may be adventive there. Euphorbia glyptosperma is characterized by its prominently ridged seeds, laciniate stipules, complete lack of pubescence, and somewhat obscure toothing near the tips of the leaves. (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. 269. | FNA vol. 12, p. 245. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Chamaesyce glyptosperma | E. eriogonoides, Tithymalopsis curtisii, T. eriogonoides |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 187. (1859) | Engelmann ex Chapman: Fl. South. U.S., 401. (1860) |
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