Euphorbia ipecacuanhae |
Euphorbia ouachitana |
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American ipecac, Carolina ipecac, ipecac spurge |
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Habit | Herbs, perennial, with deep, stout rootstock. | Herbs, annual, with taproot. |
Stems | decumbent or slightly ascending, branched, often densely clumped, previous year's dead stems not persistent, 17–27 cm, usually glabrous, rarely sparsely villous. |
erect-ascending, often basally decumbent, often branched near base, 12–28 cm, glabrous. |
Leaves | alternate; stipules 0.1–0.2 mm; petiole (0–)1–2 mm, glabrous; blade usually linear, obovate, or oblanceolate to orbiculate, rarely filiform, proximal greatly reduced, scalelike, 15–70 × 1.5–13 mm gradually smaller proximally, base cuneate, margins entire, apex rounded, broadly acute, or emarginate, surfaces glabrous; venation occasionally obscure on smaller leaves, midvein conspicuous. |
petiole 0–3 mm; blade broadly oblanceolate to subspatulate, or proximalmost often orbiculate, 3–20 × 3–9 mm, base attenuate, margins entire, apex rounded to emarginate, surfaces glabrous; venation pinnate, midvein prominent. |
Involucre | yellow or yellow-green, hemispheric, 1–1.2 × 2–2.4 mm, glabrous; glands 5, yellow or yellow-green, obovate or elliptic, 0.7–0.8 × 1–1.2 mm; appendages white or green, often forming narrow rim around distal margin of gland, 0–0.2 mm, entire. |
infundibular, 1.3–1.6 × 1–1.2 mm, glabrous; glands 4, crescent-shaped; 0.4–0.5 × 0.8–1 mm; horns divergent, 0.2–0.4 mm. |
Staminate flowers | 10–20. |
15–20. |
Pistillate flowers | ovary glabrous; styles 0.4–0.8 mm, 2-fid at apex. |
ovary glabrous; styles 0.8 mm, 2-fid. |
Capsules | globose, 2.3–3.4 × 3.5–4.2 mm, glabrous; columella 3–3.1 mm. |
ovoid-globose, 2.6–2.7 × 2.5–2.7 mm, slightly lobed; cocci rounded to ± flattened, smooth, glabrous; columella 2–2.1 mm. |
Seeds | white or brown, ovoid, 2.3–2.5 × 1.5 mm, angular, with 5 longitudinal ridges, shallowly and irregularly pitted; caruncle absent. |
dark brown, oblong-ovoid, 1.5–2 × 1–1.6 mm, with deep, rounded pits in 3–4 regular vertical rows; caruncle reniform-ovate, conic, 0.5–0.7 × 0.5–0.8 mm. |
Cyathia | usually in terminal dichasia, sometimes pleiochasia; peduncle 10–50(–70) mm, glabrous. |
peduncle 0.4–0.7 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3, 1–3 times 2-branched; pleiochasial bracts ovate-deltate to subrhombic-ovate, shorter and wider than distal leaves; dichasial bracts connate 1/4 length, not imbricate, broadly deltate to subreniform, base truncate to broadly obtuse, margins entire, apex obtuse to bluntly acuminate; axillary cymose branches 1–5. |
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2n | = 26. |
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Euphorbia ipecacuanhae |
Euphorbia ouachitana |
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Phenology | Flowering and fruiting early spring–early summer. | Flowering and fruiting spring. |
Habitat | Pine and pine-oak savannas, pine-oak sand hills, turkey oak scrub, open sand habitats. | Semiopen forests, bluffs and ledges, stream banks, glades. |
Elevation | 0–150 m. (0–500 ft.) | 100–400 m. (300–1300 ft.) |
Distribution |
CT; DC; DE; GA; MD; NC; NJ; NY; PA; SC; VA
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AR; MO; OK; TN; TX |
Discussion | The vegetative stems of Euphorbia ipecacuanhae are often quite short in proportion to the dichasial or pleiochasial branches, thus superficially plants often appear to have mostly opposite leaves. However, careful examination of the base of the plant will reveal alternate leaves. The leaves are extremely variable in both shape and coloration, and the variation can be pronounced within a population or even on a single plant. M. J. Huft (1979) did not recognize infraspecific taxa within E. ipecacuanhae, and his treatment is followed here. This species is found on the Atlantic coastal plain. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia ouachitana is restricted to semiopen forests and woodlands in the south-central United States. It is similar to E. commutata and has been most commonly identified as that species in the past. However, it differs in its consistently brown seeds that have pits in regular, vertical rows. The two species also differ in E. commutata’s numerous, proximal, long-petiolate elliptic leaves. The proximal leaves of E. ouachitana are spatulate with an orbiculate blade and petiolelike base. Aside from the restricted distribution of E. ouachitana in Missouri and Tennessee, the ranges of E. ouachitana and E. commutata do not overlap (see M. H. Mayfield 2013 for a detailed discussion of the distribution). Euphorbia ouachitana is most common in the Ouachita Mountains from southeastern Oklahoma to Hot Springs County, Arkansas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 247. | FNA vol. 12, p. 306. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | E. arundelana, Tithymalopsis ipecacuanhae | |
Name authority | Linnaeus: Sp. Pl. 1: 455. (1753) | Mayfield: J. Bot. Res. Inst. Texas 7: 642, figs. 2[row 2, right], 6. (2013) |
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