Euphorbia polygonifolia |
Euphorbia pinetorum |
|
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dune spurge, euphorbe à feuilles de renouée, seaside sandmat, seaside spurge |
pineland spurge |
|
Habit | Herbs, annual, with taproot. | Herbs, perennial, with thickened, woody taproot. |
Stems | usually prostrate, occasionally ascending, 5–30 cm, glabrous. |
erect, 30–100 cm, glabrous; branches ± straight. |
Leaves | opposite; stipules usually distinct, occasionally connate basally (distal portion of stem), triangular-subulate, entire or divided, 0.8–1.5 mm, glabrous; petiole 1–3 mm, glabrous; blade oblong, linear-oblong, or linear-lanceolate, 5–16 × 2–4 mm, base slightly asymmetric, obtuse or subcordate, margins entire, apex obtuse, often mucronulate, surfaces uniformly green or reddish tinged, glabrous; venation obscure. |
usually alternate, occasionally opposite proximally; petiole 0–1.5 mm, glabrous; blade narrowly lanceolate to linear, base long-attenuate, 30–120 × 2.5–5 mm, margins usually entire, occasionally with few inconspicuous teeth, revolute, apex narrowly acute, surfaces glabrous; venation obscurely pinnate, midvein prominent. |
Involucre | obconic-campanulate, 1.2–1.7 × 1–1.4 mm, glabrous; glands 4, occasionally rudimentary, green-yellow to tan or orange-tinged, occasionally shortly stipitate, usually broadly oval to subcircular, sometimes figure eight-shaped, shallowly cupped, 0.1–0.3 × 0.2–0.4 mm; appendages absent or rudimentary. |
campanulate, 1.5–1.9 × 1.4–1.7 mm, glabrous; involucral lobes divided into broad, triangular segments; glands 3(–5), red to purple, sessile and broadly attached, 0.8–1.1 × 1.2–1.6 mm, opening oblong (flattened without pressing), without annular rim, glabrous; appendages absent. |
Staminate flowers | 5–14. |
8–12. |
Pistillate flowers | ovary glabrous; styles 0.7–1 mm, 2-fid 1/2 length. |
ovary glabrous; styles 1.5 mm, 2-fid nearly entire length. |
Capsules | broadly ovoid, 3–3.5(–4) × (2–)2.4–3 mm, glabrous; columella 2–3 mm. |
purpurescent, depressed-globose, 2.8–3.2 × 3.6–4 mm, 3-lobed, glabrous; columella 2.6–2.9 mm. |
Seeds | ashy white, wedge-shaped to slightly ovoid, weakly dorsiventrally compressed and elliptic-terete to bluntly subangled in cross section, back strongly rounded, face slightly rounded, (2–)2.2–2.8 × 1.6–1.9 mm, smooth or minutely pitted, with smooth brown line from top to bottom on adaxial side. |
dark brown, cylindric-ovoid to ovoid, rounded in cross section, 2.1–2.4 × 2 mm, uniformly low-tuberculate, tubercles in median, transverse ridge; caruncle absent. |
Cyathia | solitary or in small, cymose clusters at distal nodes; peduncle 0.5–5 mm. |
peduncle 1.5–3 mm. |
Cyathial | arrangement: terminal monochasial or dichasial branches 1–2, unbranched; pleiochasial bracts 2–3, often whorled, wholly purpurescent green or pink at base, similar in shape and size to distal leaves or slightly narrower; dichasial bracts highly reduced. |
|
Euphorbia polygonifolia |
Euphorbia pinetorum |
|
Phenology | Flowering and fruiting early summer–fall. | Flowering and fruiting year-round. |
Habitat | Sandy maritime and freshwater beaches and foredunes. | Sandy soils in pinelands. |
Elevation | 0–200 m. (0–700 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
CT; DE; FL; GA; IL; IN; MA; MD; ME; MI; NC; NH; NJ; NY; OH; PA; RI; SC; VA; WI; NB; NS; ON; PE; QC
|
FL |
Discussion | Euphorbia polygonifolia is native to coastal beaches and dunes along the Atlantic Ocean from the maritime provinces of Canada south to northern Florida. The species also occurs disjunctly along the shores of the North American Great Lakes. Euphorbia polygonifolia was native to Quebec but is now considered extirpated from the province. It has apparently been introduced in Europe, but it is unclear if it has persisted there (L. C. Wheeler 1941). Immature individuals of this species can be somewhat difficult to distinguish from E. bombensis where their ranges overlap (Virginia to northern Florida). Where they occur together, E. polygonifolia tends to be a pioneer species on the upper beach and foredune front, whereas E. bombensis tends to inhabit areas behind the foredune (R. D. Porcher and D. A. Rayner 2002). Euphorbia polygonifolia can be distinguished also by its larger capsules and larger, wedge-shaped to slightly ovoid seeds. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia pinetorum has a restricted distribution in southern peninsular Florida, primarily in Miami-Dade and Monroe counties. The species is very similar to narrow-leaved forms of the closely related E. cyathophora but differs in its perennial habit, consistently unlobed leaves, and purpurescent involucral glands and cyathia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 284. | FNA vol. 12, p. 323. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Poinsettia |
Sibling taxa | ||
Synonyms | Chamaesyce polygonifolia | Poinsettia pinetorum |
Name authority | Linnaeus: Sp. Pl. 1: 455. (1753) | (Small) G. L. Webster: J. Arnold Arbor. 48: 403. (1967) |
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