Euphorbia commutata |
Euphorbia maculata |
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tinted euphorbia, tinted woodland spurge |
euphorbe maculée, milk purslane, milk spurge, prostrate spurge, sandmat, spotted sandmat, spotted sandmat or spurge, spotted spurge |
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Habit | Herbs, usually biennial, occasionally annual, with taproot. | Herbs, annual, with taproot. |
Stems | erect or ascending, decumbent and often branched near base, 10–40 cm, glabrous. |
usually prostrate, occasionally with ascending tips, often mat-forming, not rooting at nodes, 5–45 cm, densely and evenly short-sericeous to sericeous or villous. |
Leaves | petiole usually 5–10 mm, 0–1 mm distally; blade usually oblanceolate to obovate, rarely ovate, 5–30 × 3–10 mm, base broadly attenuate, margins entire, apex usually obtuse to rounded, occasionally slightly retuse, surfaces glabrous; venation pinnate, midvein prominent. |
opposite; stipules distinct, linear-subulate, sometimes irregularly 2–3-lobed, 1–1.3 mm, sparsely short-sericeous to sericeous or villous; petiole 0.5–1.5 mm, moderately short-sericeous to sericeous or villous; blade oblong-ovate to ovate-elliptic or oblong-elliptic, 4–18 × 2.5–8 mm, base strongly asymmetric, one side usually angled and other ± truncate and expanded into small, rounded auricle, margins serrulate (longer side) or subentire (shorter side), apex rounded or broadly acute, abaxial surface pale grayish green, moderately to densely lanulose to villous, adaxial surface usually with irregular reddish streak along midvein, glabrate or with sparse, long, slender hairs; palmately veined at base, pinnate distally. |
Involucre | campanulate, 1.7–2.5 × 1.5–2.5 mm, glabrous; glands 4, crescent-shaped; 0.6–1 × 0.8–1.5 mm; horns divergent, 0.5–1.1 mm. |
obconic, 0.8–1 × 0.6–0.8 mm, sparsely strigose to short-sericeous; glands 4, green to yellow-green, turning pink with age, usually ± unequal, narrowly oblong to nearly linear, 0.1–0.2 × 0.2–0.5 mm; appendages white to reddish tinged, lunate to oblong, 0.1–0.3 × 0.2–1.5 mm, distal margin crenulate. |
Staminate flowers | 9–15. |
2–5. |
Pistillate flowers | ovary glabrous; styles 0.9–1.3 mm, 2-fid. |
ovary sericeous; styles 0.3–0.4 mm, 2-fid at apex. |
Capsules | ovoid-globose, 2.5–3.2 × 3 mm, slightly lobed; cocci rounded to ± flattened, smooth, glabrous; columella 1.5–2 mm. |
ovoid, well exserted from involucre at maturity, 1.3–1.5 × 1.2–1.4 mm, sparsely to moderately and evenly sericeous; columella 1–1.2 mm. |
Seeds | white to gray, broadly oblong-elliptic to ovoid or nearly globose, 1.5–2 × 1.3–1.6 mm, strongly small-pitted; caruncle irregularly winglike, conic, 0.6–1 × 0.7–0.9 mm. |
white to light brown, oblong-ovoid, sharply angular in cross section, 1–1.2 × 0.6–0.9 mm, with 3–4 low, transverse ridges that cross angles. |
Cyathial | arrangement: terminal pleiochasial branches (2–)3(–4), 1–3+ times 2-branched; pleiochasial bracts similar in shape and size to distal leaves; dichasial bracts distinct to basally subconnate, not imbricate, widely ovate, rhombic, or reniform, base cordate, rarely slightly perfoliate, margins entire, apex obtuse to rounded, mucronulate; axillary cymose branches 0–5. |
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Cyathia | peduncle 0.5–1 mm. |
solitary or in small, cymose clusters at distal nodes or on congested, axillary branches; peduncle 0.1–0.6 mm. |
2n | = 28. |
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Euphorbia commutata |
Euphorbia maculata |
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Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring–fall. |
Habitat | Bottomland and upland forests, bluffs and ledges, stream banks, glades, rarely fen margins. | Disturbed areas, fallow fields, gardens, sidewalk cracks, railroads, roadsides. |
Elevation | 50–1000 m. (200–3300 ft.) | 0–1500 m. (0–4900 ft.) |
Distribution |
AL; AR; FL; GA; IA; IL; IN; KY; LA; MD; MI; MO; MS; NC; OH; OK; PA; SC; TN; VA; WI; WV; ON
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AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; BC; NB; NS; ON; PE; QC; Mexico; Central America; South America; West Indies; Eurasia; Africa; Pacific Islands (New Zealand); Australia
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Discussion | Euphorbia maculata is a widespread weed in temperate latitudes, and it also occurs in cool climates at higher elevations in the tropics. It is presumed to be native to eastern and central North America, but given its extremely weedy tendencies, it is difficult to know for sure. It spreads readily in association with greenhouse plants and earth-moving activities, and it is notorious for its ability to colonize sidewalk cracks in the summer, even in congested cities. The name E. maculata was misapplied by most earlier botanists (for example, L. C. Wheeler 1941) to plants with ascending stems that are treated here as E. nutans. D. G. Burch (1966) reviewed the sources of data used by Linnaeus in his original description and concluded that the name E. maculata applies to this prostrate-stemmed taxon. For further discussion of the distinctions between E. maculata and the similar 47. E. humistrata, see the treatment of that species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 300. | FNA vol. 12, p. 275. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Galarhoeus austrinus, G. commutatus, Tithymalus commutatus | Chamaesyce maculata, C. mathewsii, C. supina, C. tracyi, E. supina |
Name authority | Engelmann: in A. Gray, Manual ed. 2, 389. (1856) | Linnaeus: Sp. Pl. 1: 455. (1753) |
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