Euphorbia chamaesula |
Euphorbia lathyris |
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mountain spurge |
caper spurge, euphorbe épurge, gopher plant, gopher spurge, mole plant |
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Habit | Herbs, perennial, with thick rootstock. | Herbs, annual or biennial, with taproot. |
Stems | erect, branched, 40–90 cm, glabrous. |
erect, unbranched or branched, 200 cm, glabrous, glaucous. |
Leaves | petiole 0.5–1 mm; blade elliptic to oblong, 8–20(–40) × 3–6 mm, base truncate, rounded, or attenuate, margins entire, apex obtuse or acute, sometimes slightly mucronate, surfaces glabrous; venation inconspicuous, only midvein prominent. |
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. |
Involucre | turbinate or campanulate, 1.5–2.5 × 1.1–1.9 mm, glabrous; glands 4, crescent-shaped to semicircular, 0.5–0.8 × 1–1.8 mm; horns usually convergent, 0.2–0.8 mm. |
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. |
Staminate flowers | 8–12. |
25–30. |
Pistillate flowers | ovary glabrous; styles 1–1.8 mm, 2-fid. |
ovary glabrous; styles 0.7–2.2 mm, 2-fid. |
Capsules | depressed-ovoid, 4.3–5 × 5–6 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 3.5–4 mm. |
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. |
Seeds | gray to dark brown, ovoid-oblong, truncate at both ends, 2.6–3.4 × 2–2.6 mm, shallowly pitted to almost smooth; caruncle conic, 1 × 0.8 mm. |
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. |
Cyathial | arrangement: terminal pleiochasial branches 3–5(–6), each 3–4 times 2-branched; pleiochasial bracts ovate-lanceolate to slightly subpandurate, similar in size or wider than distal leaves; dichasial bracts distinct, lanceolate to broadly ovate, base usually truncate to rounded or subcordate, sometimes attenuate, margins entire or slightly crenulate, apex usually obtuse to acute, occasionally acuminate; axillary cymose branches 2–8. |
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. |
Cyathia | peduncle 1–3 mm. |
peduncle 0–0.5 mm. |
2n | = 26. |
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Euphorbia chamaesula |
Euphorbia lathyris |
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Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting winter–fall. |
Habitat | Clearings in ponderosa pine forests, montane roadsides, dry streambeds, creek banks, sandy and gravelly soils. | Roadsides, cultivated fields, stream banks, waste places. |
Elevation | 1700–2700 m. (5600–8900 ft.) | 0–1800 m. (0–5900 ft.) |
Distribution |
AZ; NM; Mexico (Chihuahua, Sonora)
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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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Discussion | Euphorbia chamaesula is easily distinguished from other perennial members of subg. Esula in western North America by its larger capsules and the vegetative shoots (without cyathia) that arise from the distal nodes of the stem proximal to the pleiochasia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 12, p. 300. | FNA vol. 12, p. 304. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Tithymalus chamaesula | Galarhoeus lathyris, Tithymalus lathyris |
Name authority | Boissier: Cent. Euphorb., 38. (1860) | Linnaeus: Sp. Pl. 1: 457. (1753) — (as lathyrus) |
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