Euphorbia lathyris |
Euphorbia bicolor |
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caper spurge, euphorbe épurge, gopher plant, gopher spurge, mole plant |
snow-on-the-prairie |
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Habit | Herbs, annual or biennial, with taproot. | Herbs, annual, with taproot. |
Stems | erect, unbranched or branched, 200 cm, glabrous, glaucous. |
erect, unbranched or branched, 40–100 cm, pilose. |
Leaves | opposite, decussate; petiole absent; blade linear to oblong-lanceolate, 30–120 × 3–25 mm, base acute, rounded, cordate or clasping, margins entire, apex acute or subobtuse, sometimes mucronate, surfaces glabrous, abaxial ± glaucous; venation pinnate, midvein prominent. |
alternate; stipules 0.3–0.4 mm; petiole 0.3–1 mm, pilose; blade narrowly elliptic to lanceolate, 37–54 × 7–17 mm, base cuneate to slightly rounded, margins entire, apex aristate or acute, surfaces pilose; venation obscure, only midvein conspicuous. |
Involucre | campanulate, 1.2–2.3 × 1.4–2.5 mm, glabrous; glands 4, elliptic, 0.3–0.6 × 1–1.3 mm; horns divergent, thick, tips rounded, dilated, 0.5–1.4 mm. |
campanulate, 2.7–3.5 × 2.2–3 mm, densely pilose; glands 4–5, green to pale greenish yellow, reniform, 0.6–0.7 × 1.4–1.6 mm; appendages white, obdeltate to orbiculate, 1.4–2.5 × 1.7–3 mm, dentate to erose. |
Staminate flowers | 25–30. |
30–70. |
Pistillate flowers | ovary glabrous; styles 0.7–2.2 mm, 2-fid. |
ovary pilose; styles 0.7–1.2 mm, 2-fid 1/2 length. |
Capsules | depressed-globose, 9–12 × 12–16 mm, deeply 3-lobed, tardily dehiscent and appearing indehiscent, mesocarp spongy; cocci rounded, smooth, glabrous; columella 4–5.2 mm. |
depressed-ovoid, 3.5–7.5 × 6–8.7 mm, densely pilose; columella 4.5–5.5 mm. |
Seeds | brownish or blackish, oblong, 4.5–6 × 3–4.2 mm, rugose, irregularly reticulate; caruncle substipitate, hat-shaped, 1.6–2 × 1.2–1.5 mm. |
tan to brown, ovoid, 4.3–4.5 × 3.7–3.9 mm, alveolate; caruncle absent. |
Cyathial | arrangement: terminal pleiochasial branches 2–4, each 1–2 times 2-branched; pleiochasial bracts cordate-lanceolate, shorter and wider than distal leaves; dichasial bracts distinct, ovate-oblong to lanceolate, base subcordate, margins entire, apex acute; axillary cymose branches 0–10. |
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Cyathia | peduncle 0–0.5 mm. |
in terminal pleiochasia dichasial and pleiochasial bracts linear to narrowly oblanceolate, with conspicuous white margins; peduncle 1.2–3 mm, densely pilose. |
Euphorbia lathyris |
Euphorbia bicolor |
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Phenology | Flowering and fruiting winter–fall. | Flowering and fruiting summer–fall. |
Habitat | Roadsides, cultivated fields, stream banks, waste places. | Prairies, blackland (calcareous) prairies, pastures and clearings in former blackland prairie areas, roadside clearings. |
Elevation | 0–1800 m. (0–5900 ft.) | 100–200 m. (300–700 ft.) |
Distribution |
AZ; CA; CT; ID; IL; MA; MD; MT; NC; OH; OR; PA; SC; TN; TX; VA; WA; WV; BC; ON; QC; Europe; Asia; Africa [Introduced in North America; introduced also in Mexico, South America, Australia]
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AR; LA; OK; TX
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Discussion | Euphorbia lathyris is most likely native to the central and eastern Mediterranean region, but it is widely cultivated and often locally escaped in temperate regions worldwide, as in the flora area. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia bicolor is similar in appearance to E. marginata but can be distinguished by its linear to narrowly oblanceolate bracts and the presence of hairs on all parts of the plant. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 304. | FNA vol. 12, p. 243. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Galarhoeus lathyris, Tithymalus lathyris | |
Name authority | Linnaeus: Sp. Pl. 1: 457. (1753) — (as lathyrus) | Engelmann & A. Gray: Boston J. Nat. Hist. 5: 233. (1845) |
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