Euphorbia prostrata |
Euphorbia platyphyllos |
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blue weed, ground spurge, prostrate sandmat, prostrate spurge or sandmat |
broad-leaf spurge |
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Habit | Herbs, annual, with taproot. | Herbs, annual, with taproot. |
Stems | prostrate to decumbent, usually not mat-forming, 10–30 cm, crisped-villous to glabrate (proximally). |
erect, unbranched or branched, 15–80 cm, usually glabrous, rarely pilose. |
Leaves | opposite; stipules connate (lower side) or distinct (upper side), triangular-subulate, often lacerate distally, 0.5–1 mm, short crisped-villous to glabrate; petiole 0.5–1.5 mm, usually short crisped-villous, sometimes wooly at distal nodes; blade broadly elliptic to elliptic-oblong, ovate-spatulate, or ovate, 3–11(–15) × 3–6(–8) mm, base slightly asymmetric, rounded to slightly cordate and oblique, margins serrulate at least in distal 1/2, sometimes obscurely so, apex obtuse, abaxial surface finely crisped-villous, adaxial surface usually glabrous or glabrate, sometimes sparsely crisped-villous; 3-veined from base. |
petiole absent; blade oblanceolate or obovate, 20–50 × 5–10 mm, base subcordate or cuneate, margins finely serrulate, apex usually acute, occasionally obtuse, occasionally mucronulate, surfaces usually sparsely pilose, occasionally glabrate; venation pinnate, midvein prominent. |
Involucre | obconic, 0.6–0.9 × 0.5 mm, crisped-villous or glabrous; glands 4, reddish, oval to oblong, 0.1 × 0.1–0.2 mm; appendages white to pink, rudimentary, 0–0.2 mm, distal margin entire or irregularly scalloped. |
cupulate, 0.9–1.2 × 1.3–1.6 mm, sparsely pilose; glands 4, elliptic to ovate, 0.5–0.7 × 0.7–1 mm; horns absent. |
Staminate flowers | 3–6. |
10–12. |
Pistillate flowers | ovary densely crisped-villous; styles 0.1 mm, 2-fid nearly entire length. |
ovary glabrous, styles 1.6–1.8 mm, 2-fid. |
Capsules | broadly ovoid, 1.2–2 × 1.4–1.5 mm, crisped-villous along keels and toward base, often glabrous between keels; columella 1–1.2 mm. |
globose or subglobose, 2.5–3 × 2.5–3 mm, slightly 3-lobed; cocci rounded, sparsely verrucose, glabrous; columella 1.9–2.1 mm. |
Seeds | white but with barely concealed brown surface beneath, ovoid, sharply 4-angled in cross section, abaxial faces plane to convex, adaxial faces concave, 0.8–1.1 × 0.5–0.7 mm, with several narrow, sharp, slightly irregular, transverse ridges. |
dark brown, ovoid, dorsiventrally compressed, 2–2.2 × 1.5–1.7 mm, smooth; caruncle ± reniform, 0.2–0.5 × 0.2–0.5 mm. |
Cyathia | solitary or in small, cymose clusters at distal nodes or on congested, axillary branches; peduncle 1–2 mm. |
peduncle absent. |
Cyathial | arrangement: terminal pleiochasial branches (3–)5, proximalmost node 3-branched, more distal ones 1–3 times 2-branched; pleiochasial bracts similar in shape and size to distal leaves; dichasial bracts distinct, ovate-triangular, base obtuse, margins finely serrulate, apex obtuse, mucronulate; axillary cymose branches 0–7(–14). |
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2n | = 18. |
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Euphorbia prostrata |
Euphorbia platyphyllos |
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Phenology | Flowering and fruiting early spring–fall. | Flowering and fruiting summer–fall. |
Habitat | Disturbed areas, fields, gardens, sidewalks, sandy places, ballast piles. | Lake shores, roadsides, waste places. |
Elevation | 0–1400 m. (0–4600 ft.) | 0–500 m. (0–1600 ft.) |
Distribution |
AL; AR; AZ; CA; CO; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NE; NM; OH; OK; PA; SC; SD; TN; TX; UT; VA; WV; WY; Mexico; Central America; South America; West Indies [Introduced in Eurasia, Africa, Pacific Islands, Australia]
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MA; MI; NC; NY; OH; PA; RI; TN; VT; WA; ON; s Europe [Introduced in North America; introduced also in South America (Argentina, Chile, Paraguay)] |
Discussion | Euphorbia prostrata is native to tropical America and possibly into the southern part of the flora area. It is likely adventive throughout most of the northern part of its range. It is widely naturalized throughout much of the rest of the tropics. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 285. | FNA vol. 12, p. 307. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Chamaesyce prostrata | Galarhoeus platyphyllos, Tithymalus platyphyllos |
Name authority | Aiton: Hort. Kew. 2: 139. (1789) | Linnaeus: Sp. Pl. 1: 460. (1753) |
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