Euphorbia serpens |
Euphorbia nutans |
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creeping spurge, Matted sandmat, Matted spurge, round-leafed spurge |
eyebane, eyebane sandmat, eyebane spurge, nodding or upright spotted spurge, nodding spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, annual, with taproot. |
Stems | prostrate, frequently mat-forming and rooting at nodes, 15–50 cm, glabrous. |
usually ascending, occasionally erect, often arched at tips, 20–80 cm, sparsely to moderately pilose to villous or with short, incurved hairs, hairs often concentrated at nodes and distally, occasionally in 2 bands along opposite sides of stem. |
Leaves | opposite; stipules connate into conspicuous, deltate scale, white to pink, membranaceous, 0.5–1(–1.2) mm, glabrous; petiole less than 1 mm, glabrous; blade ovate, oblong or orbiculate, 2–7(–9) × 2–6 mm, base asymmetric, rounded to subcordate, margins entire, apex rounded, surfaces without red blotch, glabrous; usually only midvein conspicuous. |
opposite; stipules usually distinct, sometimes connate basally on one side of stem, small scales, irregularly toothed, fringed, or divided, 1–1.5 mm, sparsely to moderately villous distally; petiole 0.3–1.6 mm, moderately pilose to villous; blade oblong to oblong-lanceolate, 8–40 × 3–12 mm, base asymmetric, one side usually angled or rounded, other side ± truncate to cordate-auriculate, margins serrulate, apex angled with blunt tip, abaxial surface pale green or faintly to strongly reddish tinged, adaxial surface usually reddish-mottled or with conspicuous reddish spot, both surfaces usually sparsely to moderately pilose, especially toward base, sometimes glabrous; 3–5-veined from base, pinnate distally, veins faint. |
Involucre | campanulate to turbinate, 0.3–0.7(–1) × 0.4–0.6 mm, glabrous; glands 4, yellow, oblong, 0.1 × 0.2 mm; appendages white to pinkish, equal, forming narrow rim at edge of gland, 0.1–0.2 × 0.2–0.3 mm, distal margin entire or crenulate. |
narrowly obconic, 0.5–1 × 0.3–0.7 mm, glabrous; glands 4, usually green, sometimes reddish purple, oblong to nearly circular, 0.2–0.4 × 0.3–0.5 mm; appendages white or pinkish, ovate to broadly elliptic, 0.2–1 × 0.2–1.5 mm, distal margin entire. |
Staminate flowers | 5–10. |
5–28. |
Pistillate flowers | ovary glabrous; styles 0.2 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous; styles 0.6–2.5 mm, 2-fid 1/2 length. |
Capsules | broadly ovoid, oblate, or subglobose, 1.3–1.4 × 1.3–1.7 mm, glabrous; columella (0.9–)1–1.2 mm. |
ovoid, 1.6–2.3 × 1.5–2.4 mm, glabrous; columella 1.4–1.6 mm. |
Seeds | white to gray or light pink, ovoid, bluntly 3–4-angled in cross section, 0.7–1.1 × 0.4–0.7 mm, smooth. |
dark brown, sometimes with thin, white coating (often more persistent along angles than faces), elliptic-ovoid to ovoid, rounded-angular in cross section, 1–1.6 × 0.5–0.8 mm, surface finely and irregularly wrinkled, sometimes faintly so, or with indistinct, shallow, rounded cross ridges. |
Cyathia | solitary at distal nodes; peduncle 0.5–1(–2.5) mm. |
solitary at distal nodes or in small, cymose clusters at branch tips; peduncle 0.5–2.5 mm. |
2n | = 12, 14, 22. |
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Euphorbia serpens |
Euphorbia nutans |
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Phenology | Flowering and fruiting year-round (in warmer areas) or summer (in temperate regions). | Flowering and fruiting spring–early fall. |
Habitat | Mostly sandy or well-drained soils, desert scrub, coastal scrub, chaparral, oak and juniper woodlands, sand dunes, riparian forests, mesquite grasslands, prairies, coniferous and deciduous hardwood forests, disturbed areas. | Stream banks, pond edges, disturbed portions of upland prairies, mesic to dry upland forest openings, pastures, fallow fields, railroads, roadsides, gardens, disturbed areas. |
Elevation | 0–2000 m. (0–6600 ft.) | 0–1600 m. (0–5200 ft.) |
Distribution |
AL; AR; AZ; CA; CO; FL; GA; IA; IL; IN; KS; KY; LA; MI; MO; MS; MT; ND; NE; NJ; NM; OH; OK; PA; SD; TN; TX; UT; VT; WY; ON; SK; Mexico; Central America; South America; West Indies; Bermuda [Introduced in Europe, Asia, Africa, Australia]
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AL; AR; CA; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NM; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; WY; ON; QC; Mexico; Central America; South America; West Indies [Introduced in Eurasia]
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Discussion | Euphorbia serpens is one of the most widespread species of the genus in the New World. While it may be indigenous to a portion of the flora area, probably in the warmer, southern part of its range, it is weedy and has likely been introduced in many parts of the flora area, such as Canada and the eastern United States. It is also widely distributed in the Old World, where it is certainly introduced. The strictly prostrate habit with stems rooting at the nodes is characteristic. Euphorbia serpens is often confused with E. albomarginata, a species distributed in the southwestern United States; in addition to the features mentioned in the key, an easy and reliable way to distinguish between them is by the size of the involucral gland appendages: those of E. albomarginata are conspicuous to the naked eye, whereas those of E. serpens are inconspicuous. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia nutans is probably native to at least central and eastern North America, but given its strongly weedy tendencies, it is difficult to know where it may be adventive in parts of the flora area. It is certainly introduced where it occurs in the Old World and probably in South America as well. D. G. Burch (1966) discussed the problems of assigning names to the four main entities in this nomenclatural complex (E. hypericifolia, E. hyssopifolia, E. lasiocarpa, and E. nutans) and determined that the oldest valid name for the relatively robust, temperate North American plants with ascending stems is E. nutans. See the treatment of 56. E. maculata for a discussion of the misapplication of that name to E. nutans. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 286. | FNA vol. 12, p. 278. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce serpens | Chamaesyce lansingii, C. nutans, E. lansingii, E. preslii |
Name authority | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 2(fol.): 41; 2(qto.): 52. (1817) | Lagasca: Gen. Sp. Pl., 17. (1816) |
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