Euphorbia glyptosperma |
Euphorbia vallis-mortae |
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corrugate-seed spurge, rib-seed sandmat, ridge-seed spurge |
Death Valley sandmat |
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Habit | Herbs, annual, with taproot. | Herbs, perennial, with thickened, woody taproot. |
Stems | prostrate, loosely mat-forming, 5–40 cm, glabrous, sometimes slightly glaucous. |
prostrate to ascending, often mat-forming, 10–45 cm, pilose to villous. |
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. |
opposite; stipules distinct or connate, subulate to filiform, 0.4–1.1 mm, densely tomentose; petiole 0.4–1 mm, pilose to villous; blade suborbiculate to oblong-ovate, 3–8 × 2–6 mm, base slightly asymmetric, rounded, margins entire, apex rounded to obtuse, surfaces pilose to villous; 3-veined at base, midvein conspicuous, venation often obscured by pubescence. |
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-campanulate, 1.2–2.3 × 1–1.8 mm, densely pilose to villous; glands 4, yellow to red, subcircular to oblong, 0.2–0.5 × 0.4–0.9 mm; appendages white, flabellate to oblong, 0.1–0.7 × 0.5–1.9 mm, distal margin entire or crenulate, adaxial surface ciliate-puberulent. |
Staminate flowers | 1–5. |
15–22(–50). |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid 1/2 length. |
ovary densely pilose; styles 0.4–0.8 mm, 2-fid 1/2 length. |
Capsules | broadly ovoid, 1.3–1.9 × 1.6–2 mm, glabrous; columella 1.3–1.5 mm. |
ovoid, 1.5–2.2 × 1.8–2.2 mm, tomentose; columella 1.2–1.6 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. |
white, gray, or light brown, ovoid, sharply 4-angled in cross section, abaxial faces slightly convex, adaxial faces concave, 1.2–1.7 × 0.6–0.9 mm, smooth. |
Cyathia | solitary or in small, cymose clusters at distal nodes; peduncle 0.5–1.6 mm. |
solitary at distal nodes; peduncle 0.5–1.8 mm. |
2n | = 22. |
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Euphorbia glyptosperma |
Euphorbia vallis-mortae |
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Phenology | Flowering and fruiting early summer–fall. | Flowering and fruiting late spring–fall. |
Habitat | Stream and river banks, sand prairies, loess hill prairies, meadows, ballast, open disturbed areas, roadsides. | Roadsides, desert scrub, streamsides, sandy washes. |
Elevation | 0–1800 m. (0–5900 ft.) | 700–2000 m. (2300–6600 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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CA |
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.) |
The specific epithet of Euphorbia vallis-mortae is a misnomer because the species does not occur in Death Valley; instead, it is found at the transition of the northern edge of the Mojave Desert and the foothills of the southern Sierra Nevada in Inyo, Kern, and San Bernardino counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 269. | FNA vol. 12, p. 291. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce glyptosperma | Chamaesyce vallis-mortae |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 187. (1859) | (Millspaugh) J. T. Howell: Madroño 2: 19. (1931) |
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