Euphorbia dentata |
Euphorbia misera |
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green poinsettia, tooth poinsettia, tooth spurge |
cliff spurge |
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Habit | Herbs, annual, with taproot. | Shrubs, soft wooded, with woody rootstock. |
Stems | erect or ascending, 15–60 cm, both pilose and inconspicuously strigillose; branches usually ± straight, occasionally proximal branches arcuate. |
erect to ascending, often gnarled and scraggly, branched, with conspicuous knobby short shoots, 70–150 cm, puberulent-tomentose, bark grayish red to light gray. |
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. |
alternate, well spaced on long shoots or fasciculate on short shoots; stipules 0.6–1.1 mm; petiole 4–12(–19) mm, slender, puberulent to shortly pilose; blade oblong, ovate, orbiculate, elliptic, or obovate, 6–24 × 5–21 mm, base rounded to cuneate, margins entire, apex acute to obtuse, surfaces puberulent-tomentose; venation 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, 1.4–3.8 × 2.1–4.4 mm, puberulent-tomentose; glands 5, yellow to reddish, oblong to reniform, 0.7–1.3 × 1.1–2.6 mm; appendages green-yellow to yellowish or whitish, oblong to transversely oblong, 0.6–1.9 × 1.3–3.8 mm, crenulate to erose. |
Staminate flowers | 8–10. |
40–50. |
Pistillate flowers | ovary glabrous, styles 1.2 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous or puberulent; styles 1.6–2.7 mm, 2-fid at apex. |
Capsules | depressed-globose, 2.5–2.8 × 3.5–4 mm, 3-lobed, glabrous; columella 1.8–2.1 mm. |
oblate, 4.6–5.1 × 6.1–6.7 mm, usually glabrous or glabrescent, occasionally puberulent; columella 2.8–3.6 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. |
grayish, subglobose to ovoid, rounded in cross section, 2.7–3.3 × 2.5–2.8 mm, foveolate; caruncle absent. |
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. |
usually solitary on short shoots, peduncle 1.8–10.5 mm, puberulent-tomentose. |
2n | = 28. |
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Euphorbia dentata |
Euphorbia misera |
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Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting year-round (but most prolific after winter rains). |
Habitat | Bottomland forests, stream and river banks, bluffs, prairies, glades, fallow fields, roadsides, railroad cinders, open disturbed areas. | Rocky soils, sometimes in crevices of vertical cliff faces, coastal scrub, maritime desert scrub, arid desert scrub. |
Elevation | 0–1000 m. (0–3300 ft.) | 0–400 m. (0–1300 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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CA; Mexico (Baja California, Baja California Sur, Sonora)
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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 misera is relatively infrequent within the flora area, known primarily from coastal southern California and the Channel Islands (although a relictual inland population occurs in the Little San Bernardino Mountains). The species has been considered worthy of conservation, but appears to be under little threat, especially in Mexico where it is frequent and often locally abundant. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 321. | FNA vol. 12, p. 249. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Poinsettia dentata | |
Name authority | Michaux: Fl. Bor.-Amer. 2: 211. (1803) | Bentham: Bot. Voy. Sulphur, 51. (1844) |
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