Euphorbia glyptosperma |
Euphorbia macropus |
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corrugate-seed spurge, rib-seed sandmat, ridge-seed spurge |
Huachuca Mountain spurge |
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Habit | Herbs, annual, with taproot. | Herbs, perennial, with thick, globose to elongated tubers, 2–8 cm. |
Stems | prostrate, loosely mat-forming, 5–40 cm, glabrous, sometimes slightly glaucous. |
erect to ascending, branched, 10–45(–60) cm, glabrous, puberulent, or densely hirsute to setose, often with 2-layered indumentum of long hairs intermixed with short hairs. |
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 whorled distally, or rarely with 1–2 alternate leaves; stipules 0.1–0.2 mm; petiole 0–18 mm, hirsute, sericeous, or strigose; blade linear to ovate or almost orbiculate, 6–54 × 2–19 mm, base rounded to attenuate, margins entire, occasionally ciliate with stiff recurved hairs, apex acute to obtuse, surfaces usually hirsute, sericeous, or strigose, occasionally glabrous adaxially; venation 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. |
obconic to campanulate, 1.1–1.4 × 0.5–1.5 mm, glabrous or strigillose; glands 4–5, greenish, oblong, 0.2 × 0.4–0.5 mm; appendages usually yellowish or green, rarely dark purple, ovate, flabellate, semiorbiculate, or oblong, 0.3–0.9 × 0.4–1.1 mm, usually entire. |
Staminate flowers | 1–5. |
10–15. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid 1/2 length. |
ovary glabrous, sericeous, or strigillose; styles 0.4–0.6 mm, 2-fid 1/2 length. |
Capsules | broadly ovoid, 1.3–1.9 × 1.6–2 mm, glabrous; columella 1.3–1.5 mm. |
oblate, 2.3–3 × 3.1–4.2 mm, glabrous, sericeous, or strigillose; columella 1.6–2.1 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. |
black to light brown, broadly ovoid to subglobose, rounded in cross section, 1.5–2.3 × 1.4–1.8 mm, smooth or with low rounded tubercles; caruncle absent. |
Cyathia | solitary or in small, cymose clusters at distal nodes; peduncle 0.5–1.6 mm. |
in weakly-defined terminal dichasia; peduncle 1.4–5.8 mm, glabrous. |
2n | = 22. |
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Euphorbia glyptosperma |
Euphorbia macropus |
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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. | Stream banks and rocky slopes in pine-oak woodlands, sometimes with juniper, Douglas fir-pine forests. |
Elevation | 0–1800 m. (0–5900 ft.) | 1500–2200m. (4900–7200ft.) |
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; Mexico; Central America (Guatemala, Honduras) |
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 macropus is a widespread and common Mexican species just barely entering the flora area in southeastern Arizona, where most of the collections are from the Huachuca Mountains. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 269. | FNA vol. 12, p. 248. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Chamaesyce glyptosperma | Anisophyllum macropus, E. biformis, E. plummerae |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 187. (1859) | (Klotzsch & Garcke) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 52. (1862) |
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