Euphorbia davidii |
Euphorbia inundata |
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David's poinsettia, David's spurge, tooth poinsettia, tooth spurge |
Florida pineland spurge |
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Habit | Herbs, annual, with taproot. | Herbs, perennial, with thickened rootstock. | ||||
Stems | erect or ascending, 20–70 cm, both coarsely and sparsely hirsute and closely strigillose; branches usually ± straight, occasionally proximal branches arcuate. |
erect or ascending, 15–40 cm. |
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Leaves | usually opposite, occasionally alternate at distal nodes; petiole 7–25 mm, strigose; blade usually narrowly to broadly elliptic, occasionally lance-elliptic, 10–100 × 5–35 mm, base cuneate to attenuate, margins coarsely crenate-dentate, strigose, revolute to nearly flat, apex broadly acute to acuminate, or obtuse, abaxial surface strigose with stiff, strongly tapered hairs, adaxial surface sparsely strigose-hirsute; venation pinnate, midvein prominent. |
petiole absent or indistinct, blade linear to linear-elliptic or lanceolate, (25–)30–60(–115) × 1.5–14(–15) mm, chartaceous, base attenuate, apex acuminate, acute, or rounded and mucronate; only midvein evident. |
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Involucre | cylindric, 2.5–3 × 1.3–1.8 mm, glabrous; involucral lobes divided into 5–7 linear, papillate lobes; gland 1, yellow-green, sessile and broadly attached, 0.9 × 1.3 mm, opening oblong, glabrous; appendages absent. |
obconic or campanulate, 1.3–3.2 × 1.6–3.6 mm, lobes ovate, oblong, or nearly rectangular, 0.6–1 mm, laciniate-ciliate; glands red to greenish, oblong or nearly circular, 0.8–1 × 1.1–2 mm, distal margins crenulate-erose, undulate, or entire. |
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Staminate flowers | 5–8. |
20–25. |
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Pistillate flowers | ovary glabrous or sparsely strigose; styles 1 mm, 2-fid 1/2 to nearly entire length. |
gynophore exserted 2.6–6.1 mm, calyxlike lobes triangular to subulate, 0.6–1.4 mm; styles connate 1/8 length, 1.3–2.2 mm. |
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Capsules | broadly ovoid, 2.9–3.3 × 4–4.8 mm, 3-lobed, glabrous; columella 2.2–2.7 mm. |
oblate-ovoid, 5.1–6.1 × 6.9–8.6 mm, 3-lobed; columella 3.9–4.7 mm. |
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Seeds | black to brown or pale gray, ovoid to triangular-ovoid, angular in cross section, 2.4–2.9 × 2.2–2.9 mm, low-tuberculate, tubercles irregularly arranged or in faint, transverse row; caruncle 0.9–1.1 mm. |
brown to blackish, ovoid-globose, circular or faintly 3- or 4-angled in cross section, 2.9–3.4 × 2.7–3 mm, smooth, base flattened or rounded, apex rounded or with inconspicuous blunt point. |
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Cyathial | arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched; pleiochasial bracts 2–4, often whorled, green with diffuse greenish white to mauve near 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. |
arrangement: terminal pleiochasial branches 2–3, 5–18 cm, 3–8 times 2-branched; pleiochasial bracts linear-lanceolate or narrowly ovate, 25–49 × 5–9 mm, margins entire, apex acute or acuminate; dichasial bracts ovate or lanceolate, 6–21 × 2–6 mm, margins entire, apex acute or acuminate; axillary cymose branches 1–5. |
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Cyathia | peduncle 0.5–1 mm. |
peduncle 6–24 mm (often exceeding dichasial bracts). |
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2n | = 56. |
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Euphorbia davidii |
Euphorbia inundata |
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Phenology | Flowering and fruiting summer–fall. | |||||
Habitat | Forests, stream and riverbanks, prairies, roadsides and open disturbed areas. | |||||
Elevation | 200–1500 m. (700–4900 ft.) | |||||
Distribution |
AR; AZ; CA; CO; FL; IA; ID; IL; IN; KS; KY; LA; MA; MI; MN; MO; NC; NE; NJ; NM; NY; OH; OK; SD; TN; TX; UT; VA; VT; WI; WV; WY; ON; QC; Mexico (Chihuahua, Coahuila, Sonora) [Introduced in South America, Eurasia (China, Russia), Australia]
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AL; FL; GA; MS |
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Discussion | Euphorbia davidii is native from the southwestern United States and northern Mexico north through the southern Great Plains; it apparently is adventive elsewhere. The species is the weediest member of the E. dentata species group (following M. H. Mayfield 1997) and has become an agricultural weed in North America, South America (for example, Argentina), and in the Old World (particularly Australia and Russia). Euphorbia davidii can be distinguished from the closely similar E. dentata by its larger capsules and seeds, often more elliptic leaves, and shorter, stiffer hairs. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). Euphorbia inundata has a disjunct distribution in the southeastern United States. Allopatric, narrow-leaved populations from the west-central Florida peninsula are segregated as var. garrettii (E. L. Bridges and S. L. Orzell 2002). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 320. | FNA vol. 12, p. 314. | ||||
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Nummulariopsis | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Galarhoeus inundatus | |||||
Name authority | Subils: Kurtziana 17: 125, figs. 1, 2H–J. (1984) | Torrey ex Chapman: Fl. South. U.S., 402. (1860) | ||||
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