Euphorbia heterophylla |
Euphorbia polyphylla |
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Mexican fireplant, painted euphorbia |
lesser Florida spurge |
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Habit | Herbs, annual, with taproot. | Herbs, perennial, with spreading rootstock. |
Stems | erect-ascending, 20–100 cm, sparsely pilose to villous; branches ± straight. |
erect or ascending, branched, solitary, few, or occasionally densely clumped, previous year's dead stems not persistent, 18–33 cm, glabrous. |
Leaves | usually alternate, occasionally opposite proximally; petiole 10–50 mm, pilose; blade narrowly lanceolate to elliptic or broadly obovate (then usually pandurate and 4-lobed), often polymorphic on single plants, 30–200 × 20–140 mm, base acute, margins sparsely glandular-serrulate, hirtellous, flat, apex acute to obtuse, abaxial surface sparsely appressed-pilose, adaxial surface sparsely pilosulous to glabrate; venation pinnate, midvein prominent. |
alternate; stipules to 0.1 mm; petiole minute or absent; blade linear to filiform, 10–20 × 0.8–1.5(–4) mm, base cuneate, margins entire, often involute, apex rounded, surfaces glabrous; venation usually obscure, midvein visible at base of wider leaves. |
Involucre | usually campanulate, occasionally nearly hemispheric, 1.5–1.9 × 1.2–1.8 mm, glabrous; involucral lobes divided into several linear, smooth lobes; gland 1, yellow-green, stipitate, clavate, 1–1.4 × 1–1.2 mm, opening circular (occasionally flattened from pressing), with annular rim, glabrous; appendages absent. |
campanulate, 1.2–2 × 1.3–1.8 mm, glabrous or strigose on distal extreme; glands 5, red, elliptic, 0.5 × 1 mm; appendages white, orbiculate, 0.5–0.8 × 1.3–1.5 mm, erose. |
Staminate flowers | 8–15. |
20–25. |
Pistillate flowers | ovary glabrous or puberulent; styles 0.8–1.3 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous; styles 0.6–1 mm, 2-fid at apex. |
Capsules | broadly ovoid, 2.8–3.8 × 4–5.3 mm, 3-lobed, usually glabrous, rarely sparsely puberulent; columella 2.1–2.8 mm. |
globose, 2.3–2.8 × 4.3–5.1 mm, glabrous; columella 2.5–3.2 mm. |
Seeds | brown-gray to ashy gray, broadly deltoid, 2.4–2.8 × 1.9–2.4 mm, angular in cross section, dorsal face strongly acute-carinate, tuberculate, with broad rounded tubercles in 2 rows; caruncle 0.1 mm. |
ashy gray, ovoid, 2.9 × 2 mm, with obscure shallow depressions; caruncle absent. |
Cyathial | arrangement: terminal dichasial branches usually 2, occasionally reduced to congested cyme, 1–2-branched (often congested and difficult to discern); pleiochasial bracts 2–4, often whorled, wholly green or paler green at base, similar in shape and size to distal leaves; dichasial bracts highly reduced, rarely absent in highly congested clusters. |
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Cyathia | peduncle 0.9–1.5 mm. |
in terminal dichasia or pleiochasia; peduncle 2–6 mm (to 20 mm for central cyathium), glabrous. |
2n | = 28. |
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Euphorbia heterophylla |
Euphorbia polyphylla |
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Phenology | Flowering and fruiting nearly year-round. | Flowering and fruiting late spring–late fall. |
Habitat | Disturbed areas, roadsides. | Open sand and pine savannas. |
Elevation | 0–500 m. (0–1600 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
Mexico; Central America; South America [Introduced, Ala., Ariz., Calif., Fla., Ga., La., Miss., N.Mex., Tex.; introduced also in Eurasia, Africa]
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FL
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Discussion | Euphorbia heterophylla occurs from the southern United States, where it is likely naturalized, south through Mexico and Central America to South America. Because of its weediness, the precise native range in tropical and subtropical parts of the New World is not well understood. It has become widely established also in warm areas of the Old World. Leaf shape in this species is highly polymorphic within both populations and individuals. Euphorbia heterophylla can appear superficially similar to E. cyathophora but differs in its stipitate, circular involucral glands and its floral bracts that are at most very pale at the base (never colored as is typical in E. cyathophora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia polyphylla is endemic to sandy habitats in the southern half of peninsular Florida. The species has been reported from coastal Louisiana, but whether those plants represent native occurrences or plantings is unclear (R. D. Thomas and C. M. Allen 1993–1998, vol. 2). The Florida populations are here recognized as the only native occurrences. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 323. | FNA vol. 12, p. 250. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | E. geniculata, Poinsettia geniculata, P. heterophylla | Tithymalopsis polyphylla |
Name authority | Linnaeus: Sp. Pl. 1: 453. (1753) | Engelmann ex Chapman: Fl. South. U.S. ed. 2, repr. 2, 694. (1892) |
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