Euphorbia lathyris |
Euphorbia dentata |
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caper spurge, euphorbe épurge, gopher plant, gopher spurge, mole plant |
green poinsettia, tooth poinsettia, tooth spurge |
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Habit | Herbs, annual or biennial, with taproot. | Herbs, annual, with taproot. |
Stems | erect, unbranched or branched, 200 cm, glabrous, glaucous. |
erect or ascending, 15–60 cm, both pilose and inconspicuously strigillose; branches usually ± straight, occasionally proximal branches arcuate. |
Leaves | opposite, decussate; petiole absent; blade linear to oblong-lanceolate, 30–120 × 3–25 mm, base acute, rounded, cordate or clasping, margins entire, apex acute or subobtuse, sometimes mucronate, surfaces glabrous, abaxial ± glaucous; venation pinnate, midvein prominent. |
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. |
Involucre | campanulate, 1.2–2.3 × 1.4–2.5 mm, glabrous; glands 4, elliptic, 0.3–0.6 × 1–1.3 mm; horns divergent, thick, tips rounded, dilated, 0.5–1.4 mm. |
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. |
Staminate flowers | 25–30. |
8–10. |
Pistillate flowers | ovary glabrous; styles 0.7–2.2 mm, 2-fid. |
ovary glabrous, styles 1.2 mm, 2-fid 1/2 to nearly entire length. |
Capsules | depressed-globose, 9–12 × 12–16 mm, deeply 3-lobed, tardily dehiscent and appearing indehiscent, mesocarp spongy; cocci rounded, smooth, glabrous; columella 4–5.2 mm. |
depressed-globose, 2.5–2.8 × 3.5–4 mm, 3-lobed, glabrous; columella 1.8–2.1 mm. |
Seeds | brownish or blackish, oblong, 4.5–6 × 3–4.2 mm, rugose, irregularly reticulate; caruncle substipitate, hat-shaped, 1.6–2 × 1.2–1.5 mm. |
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. |
Cyathial | arrangement: terminal pleiochasial branches 2–4, each 1–2 times 2-branched; pleiochasial bracts cordate-lanceolate, shorter and wider than distal leaves; dichasial bracts distinct, ovate-oblong to lanceolate, base subcordate, margins entire, apex acute; axillary cymose branches 0–10. |
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). |
Cyathia | peduncle 0–0.5 mm. |
peduncle 0.7–1 mm. |
2n | = 28. |
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Euphorbia lathyris |
Euphorbia dentata |
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Phenology | Flowering and fruiting winter–fall. | Flowering and fruiting spring–fall. |
Habitat | Roadsides, cultivated fields, stream banks, waste places. | Bottomland forests, stream and river banks, bluffs, prairies, glades, fallow fields, roadsides, railroad cinders, open disturbed areas. |
Elevation | 0–1800 m. (0–5900 ft.) | 0–1000 m. (0–3300 ft.) |
Distribution |
AZ; CA; CT; ID; IL; MA; MD; MT; NC; OH; OR; PA; SC; TN; TX; VA; WA; WV; BC; ON; QC; Europe; Asia; Africa [Introduced in North America; introduced also in Mexico, South America, Australia]
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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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Discussion | Euphorbia lathyris is most likely native to the central and eastern Mediterranean region, but it is widely cultivated and often locally escaped in temperate regions worldwide, as in the flora area. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 12, p. 304. | FNA vol. 12, p. 321. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Poinsettia |
Sibling taxa | ||
Synonyms | Galarhoeus lathyris, Tithymalus lathyris | Poinsettia dentata |
Name authority | Linnaeus: Sp. Pl. 1: 457. (1753) — (as lathyrus) | Michaux: Fl. Bor.-Amer. 2: 211. (1803) |
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