Euphorbia glyptosperma |
Euphorbia cuphosperma |
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corrugate-seed spurge, rib-seed sandmat, ridge-seed spurge |
hairy-fruit spurge |
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Habit | Herbs, annual, with taproot. | Herbs, annual, with taproot. |
Stems | prostrate, loosely mat-forming, 5–40 cm, glabrous, sometimes slightly glaucous. |
erect, 13–20 cm, both pilose to villous and densely strigillose; branches ± straight. |
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. |
usually opposite, occasionally alternate at distal nodes; petiole 3–15 mm, pilose; blade narrowly to broadly elliptic, or lanceolate to ovate, 30–80 × 10–15 mm, base cuneate to rounded, margins coarsely crenate-dentate, strigose, revolute to nearly flat, apex broadly acute to acuminate, or obtuse, abaxial surface pilose, adaxial surface sparsely strigose-hirsute; venation pinnate, midvein prominent. |
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 to slightly cylindric, 2.3 × 1.2 mm, glabrous; involucral lobes divided into several linear, smooth lobes; gland 1, yellow-green, stipitate, clavate, 1–1.2 × 0.8–0.9 mm, opening bilabiate and oblong, glabrous; appendages absent. |
Staminate flowers | 1–5. |
3–5. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid 1/2 length. |
ovary pilose; styles 1.2 mm, 2-fid nearly entire length. |
Capsules | broadly ovoid, 1.3–1.9 × 1.6–2 mm, glabrous; columella 1.3–1.5 mm. |
broadly ovoid, 2.2–3 × 1.9–2.7 mm, 3-lobed, pilose; columella 2–2.4 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. |
gray-brown to pale gray, pyramidally ovoid, angular in cross section, 2.3–2.6 × 2.4–2.6 mm, coarsely tuberculate, tubercles in 2 transverse rows; caruncle 0.2–0.4 mm. |
Cyathia | solitary or in small, cymose clusters at distal nodes; peduncle 0.5–1.6 mm. |
peduncle 0.5–0.8 mm. |
Cyathial | arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched; pleiochasial bracts 2–4, often whorled, wholly green or paler green at base, similar in shape and size to distal leaves or slightly narrower; dichasial bracts highly reduced. |
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2n | = 22. |
= 56. |
Euphorbia glyptosperma |
Euphorbia cuphosperma |
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Phenology | Flowering and fruiting early summer–fall. | Flowering and fruiting summer–fall. |
Habitat | Stream and river banks, sand prairies, loess hill prairies, meadows, ballast, open disturbed areas, roadsides. | Open montane and canyon forests, pinyon-juniper forests, montane grasslands, stream beds, disturbed habitats. |
Elevation | 0–1800 m. (0–5900 ft.) | 800–2000 m. (2600–6600 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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AZ; NM; Mexico; Central America (Guatemala)
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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.) |
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Source | FNA vol. 12, p. 269. | FNA vol. 12, p. 319. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Poinsettia |
Sibling taxa | ||
Synonyms | Chamaesyce glyptosperma | E. dentata var. cuphosperma, Poinsettia cuphosperma |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 187. (1859) | (Engelmann) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 73. (1862) |
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