Euphorbia dentata |
Euphorbia jaegeri |
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green poinsettia, tooth poinsettia, tooth spurge |
orocopia mountains spurge |
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Habit | Herbs, annual, with taproot. | Shrubs, with woody rootstock. |
Stems | erect or ascending, 15–60 cm, both pilose and inconspicuously strigillose; branches usually ± straight, occasionally proximal branches arcuate. |
ascending, diffusely and intricately branched, 15–25 cm, usually puberulent to shortly hirsute, sometimes glabrate, bark grayish. |
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 distinct or connate, subulate, 0.3–0.5 mm, puberulent; petiole 0.7–1.1 mm, puberulent to shortly hirsute; blade ovate or elliptic, 3–9 × 1.5–5 mm, base symmetric to slightly asymmetric, rounded to cuneate, margins entire, apex usually obtuse, sometimes acute, surfaces puberulent to shortly hirsute; 3-veined from base, often 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. |
obconic to campanulate, 1.2–1.8 × 1.1–1.4 mm, puberulent to shortly hirsute; glands 4, yellow to pinkish, elliptic to oblong, 0.3 × 0.4–0.5 mm; appendages white to pink, 0.2–0.7 × 0.6–1.2 mm, irregularly divided from halfway to nearly base into 4–8 triangular to subulate segments, segments entire. |
Staminate flowers | 8–10. |
25–30. |
Pistillate flowers | ovary glabrous, styles 1.2 mm, 2-fid 1/2 to nearly entire length. |
ovary canescent; styles 0.3–0.4 mm, 2-fid entire length. |
Capsules | depressed-globose, 2.5–2.8 × 3.5–4 mm, 3-lobed, glabrous; columella 1.8–2.1 mm. |
oblate, 1.7–2.3 × 1.8–2.7 mm, puberulent; columella 1.4–2 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. |
tan to grayish, narrowly oblong-ovoid, ± 3–4-angled in cross section, 1.4–1.5 × 0.7–0.9 mm, irregularly dimpled or with faint transverse ridges that do not interrupt abaxial keel. |
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 0.5–1.7 mm. |
2n | = 28. |
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Euphorbia dentata |
Euphorbia jaegeri |
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Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting fall–spring. |
Habitat | Bottomland forests, stream and river banks, bluffs, prairies, glades, fallow fields, roadsides, railroad cinders, open disturbed areas. | Desert scrub, hillsides, arroyos, primarily in rock crevices. |
Elevation | 0–1000 m. (0–3300 ft.) | 600–900 m. (2000–3000 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 |
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 jaegeri is known only from the Orocopia Mountains of Riverside County and the Bristol and Marble Mountains of San Bernardino County. The species is one of few shrubby species of sect. Anisophyllum in the flora area. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 321. | FNA vol. 12, p. 273. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Poinsettia dentata | |
Name authority | Michaux: Fl. Bor.-Amer. 2: 211. (1803) | V. W. Steinmann & J. M. André: Aliso 30: 1, figs. 1–4. (2012) |
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