Euphorbia spathulata |
Euphorbia inundata |
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prairie spurge, reticulate seed spurge, spatulate leaf spurge, warty spurge |
Florida pineland spurge |
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Habit | Herbs, usually annual, rarely biennial, with taproot. | Herbs, perennial, with thickened rootstock. | ||||
Stems | erect or ascending, unbranched or branched, 10–70 cm, glabrous. |
erect or ascending, 15–40 cm. |
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Leaves | petiole absent or to 0.2 mm; blade oblanceolate, oblong-oblanceolate, spatulate, or cuneate, 10–50 × 6–11 mm, base broadly attenuate to rounded or shallowly cordate-clasping, margins finely serrulate (usually distally), apex usually rounded to obtuse, occasionally slightly retuse or obcordate proximally, bluntly mucronate, surfaces glabrous; 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 | campanulate to cupulate, 0.6–1(–1.5) × 0.8–1.2 mm, glabrous; glands 4–5, elliptic, oblong, to slightly reniform, 0.2–0.6 × 0.4–1 mm; horns 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 | 3–10. |
20–25. |
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Pistillate flowers | ovary glabrous; styles 0.8–1.5 mm, 2-fid. |
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 | depressed-globose, 2–3.5 × 4 mm, 3-lobed; cocci rounded, verrucose, verrucae 0.1–0.2 mm, glabrous; columella 1.4–2.2 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 | red-brown to dark purple, occasionally ± glaucous, broadly ellipsoid-ovoid to nearly globose, 1.3–2.5 × 1.5–1.8 mm, smooth, reticulate, or finely low-ridged; caruncle irregularly reniform to round, subconic to lenticular, 0.3–0.4 × 0.5–0.6 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 3(–5), each 1–3 times 2-branched; pleiochasial bracts broadly ovate to ovate-oblong, shorter and wider than distal leaves; dichasial bracts distinct, broadly ovate, ovate-triangular, or ovate-elliptic, base cordate-clasping or subcordate to rounded, margins serrulate, apex rounded to obtuse or acute; axillary cymose branches (0–4)5–12. |
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 0.3–1(–1.5) mm. |
peduncle 6–24 mm (often exceeding dichasial bracts). |
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Euphorbia spathulata |
Euphorbia inundata |
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Phenology | Flowering and fruiting spring–summer. | |||||
Habitat | Forests, fallow fields, prairies, pastures, glades, stream banks, waste places, roadsides. | |||||
Elevation | 0–3500 m. (0–11500 ft.) | |||||
Distribution |
AL; AR; AZ; CA; CO; DC; FL; GA; IA; ID; IL; IN; KS; KY; LA; MD; MI; MN; MO; MS; MT; NC; ND; NE; NM; OH; OK; OR; PA; SC; SD; TN; TX; UT; VA; WA; WI; WV; WY; ON; Mexico (Chihuahua, Sonora); s South America
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AL; FL; GA; MS |
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Discussion | As treated here, Euphorbia spathulata is a wide-ranging and variable species. J. B. S. Norton (1900) recognized a number of segregates (for example, E. arkansana, E. dictyosperma, and E. obtusata) all of which are included here in a broadly defined E. spathulata. The only segregate species that has been widely recognized in regional floras is E. obtusata (for example, M. L. Fernald 1950; T. S. Cooperrider 1995; G. Yatskievych 1999–2013, vol. 2). Authors have generally distinguished the eastern North American E. obtusata from the western E. spathulata by the former's larger seeds (1.7–2.3 mm versus 1.5–1.7 mm) with smooth (versus reticulate) surfaces, larger involucres, red (versus yellow) involucral glands, and cordate-clasping (versus rounded to subcordate) dichasial bracts. Examination of specimens of E. spathulata in the broad sense from throughout North America showed that there is some geographic patterning to seed size and surface sculpturing, but the variation does not segregate cleanly into two discrete taxa. Plants from western North America typically have small seeds (1.5–1.7 mm) with reticulate surfaces, although some western individuals have seeds 1.8–1.9 mm long with reticulate surfaces. Plants from Texas generally have small seeds (1.5–1.6 mm) but with the surfaces either reticulate or completely smooth. Plants from adjacent Louisiana have small seeds with faintly reticulate to almost bumpy surfaces. Plants from eastern North America have larger seeds (2–2.3 mm) with usually smooth surfaces, although individuals from Tennessee and the Carolinas have faintly reticulate surfaces. Involucre height, gland color, and the shape of the dichasial bracts do not segregate with seed size as previous treatments have suggested. (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. 309. | FNA vol. 12, p. 314. | ||||
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Nummulariopsis | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | E. arkansana, E. dictyosperma, E. obtusata, Galarhoeus arkansanus, G. obtusatus, Tithymalus arkansanus, T. dictyospermus, T. obtusatus, T. spathulatus | Galarhoeus inundatus | ||||
Name authority | Lamarck: in J. Lamarck et al., Encycl. 2: 428. (1788) | Torrey ex Chapman: Fl. South. U.S., 402. (1860) | ||||
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