Euphorbia dentata |
Euphorbia mesembrianthemifolia |
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green poinsettia, tooth poinsettia, tooth spurge |
coastal beach sandmat |
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Habit | Herbs, annual, with taproot. | Subshrubs or shrubs, perennial, with thickened and often woody rootstock. |
Stems | erect or ascending, 15–60 cm, both pilose and inconspicuously strigillose; branches usually ± straight, occasionally proximal branches arcuate. |
erect to ascending, or nearly decumbent in shifting sand, 25–60 cm, glabrous. |
Leaves | usually opposite, occasionally alternate at distal nodes; petiole 5–20 mm, pilose; blade 30–70 × 4–35 mm, narrowly lanceolate to suborbiculate, usually broadest below middle, base usually acute to subobtuse, rarely subtruncate, margins coarsely crenate-dentate or doubly crenate, strigillose, flat to slightly revolute, apex broadly acute, abaxial surface long pilose with weak, filiform hairs, adaxial surface sparsely pilose to glabrate; venation pinnate, midvein prominent. |
opposite; stipules connate, forming conspicuous, ligulate or deltate scale, short cleft or fringed, 1–1.8 mm, glabrous; petiole 0.5–1 mm, glabrous; blade ovate to elliptic often folded along midrib, 5–12 × 3–8 mm, ± fleshy, base slightly asymmetric, truncate to cordate, partially obscuring stem, margins entire, apex usually obtuse, rarely acute, surfaces yellowish to dark green, glabrous glaucous; obscurely 3–5-veined at base, pinnate distally, only midvein conspicuous. |
Involucre | campanulate, 3.8 × 1.8 mm, glabrous; involucral lobes divided into several linear, smooth lobes; glands (1–)2, green, sessile and broadly attached, 0.7–0.9 × 0.9–1.2 mm, opening oblong, glabrous; appendages absent. |
campanulate, 1–1.6 × 0.7–1.2 mm, glabrous; glands 4, brown, usually elliptic, occasionally almost round, 0.2–0.4 × 0.5–0.7 mm, fleshy; appendages white, oblong, rarely rudimentary, 0.2–0.4 × 0.5–0.9 mm, distal margin entire or undulate. |
Staminate flowers | 8–10. |
12–20. |
Pistillate flowers | ovary glabrous, styles 1.2 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
Capsules | depressed-globose, 2.5–2.8 × 3.5–4 mm, 3-lobed, glabrous; columella 1.8–2.1 mm. |
subglobose subtended by calyxlike structure, 1.5–2 × 2.2–2.8 mm, glabrous; columella 1–1.5 mm. |
Seeds | pale gray to black, ovoid, rounded in cross section, 2.1–2.7 × 1.7–2.1 mm, evenly minute-tuberculate; caruncle 0.4–0.6 mm. |
ashen, broadly ovoid, angled in cross section, faces plump, convex, 1.2–1.3 × 0.9–1.2 mm, obscurely pitted. |
Cyathial | arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched; pleiochasial bracts 2–4, often whorled, wholly green or paler green, white, or mauve at base, similar in shape and size to distal leaves or slightly narrower; dichasial bracts similar in shape to distal leaves but smaller (often highly reduced). |
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Cyathia | peduncle 0.7–1 mm. |
solitary at distal nodes; peduncle 0.5–1 mm. |
2n | = 28. |
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Euphorbia dentata |
Euphorbia mesembrianthemifolia |
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Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting year-round. |
Habitat | Bottomland forests, stream and river banks, bluffs, prairies, glades, fallow fields, roadsides, railroad cinders, open disturbed areas. | Sandy and rocky shores, associated beach scrub. |
Elevation | 0–1000 m. (0–3300 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AL; AR; GA; IA; IL; IN; KS; KY; LA; MD; MI; MO; MS; NC; NE; OH; OK; PA; SC; TN; TX; VA; WV; ON; Mexico (Chihuahua, Coahuila, Nuevo León, Tamaulipas)
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FL; Mexico; West Indies; Bermuda; South America (Colombia, Venezuela) |
Discussion | Euphorbia dentata is native from northern Mexico and the south central United States north and east through the Ohio River Valley. Scattered occurrences in the southeastern United States likely represent adventive populations. Reports of E. dentata as a noxious weed (from the United States and the Old World) should most likely be attributed to introductions of E. davidii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia mesembrianthemifolia is found in the flora area along the sandy and rocky shores of southern Florida from Pinellas and Volusia counties southward. It is one of the few members of subg. Chamaesyce in the flora area that is a shrub or subshrub. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 321. | FNA vol. 12, p. 277. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Poinsettia dentata | Chamaesyce buxifolia, C. mesembrianthemifolia, E. buxifolia |
Name authority | Michaux: Fl. Bor.-Amer. 2: 211. (1803) | Jacquin: Enum. Syst. Pl., 22. (1760) |
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