Euphorbia chamaesula |
Euphorbia peplus |
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mountain spurge |
petty spurge |
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Habit | Herbs, perennial, with thick rootstock. | Herbs, annual, with taproot. |
Stems | erect, branched, 40–90 cm, glabrous. |
erect, unbranched or branched, 5–30 cm, glabrous. |
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. |
petiole 1–10 mm; blade obovate, oblong, or suborbiculate, 5–25 × 4–15 mm, base attenuate or cuneate, margins entire, apex obtuse, surfaces glabrous; 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. |
cupulate to slightly turbinate, 0.6–1.1 × 0.7–0.9 mm, glabrous; glands 4, elliptic, 0.2–0.3 × 0.5–0.6 mm; horns slightly convergent to divergent, 0.4–0.6 mm. |
Staminate flowers | 8–12. |
10–15. |
Pistillate flowers | ovary glabrous; styles 1–1.8 mm, 2-fid. |
ovary glabrous; styles 0.1–0.2 mm, 2-fid. |
Capsules | depressed-ovoid, 4.3–5 × 5–6 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 3.5–4 mm. |
subglobose, 1.3–2 × 1.5–2.2 mm, slightly 3-lobed; cocci rounded, with 2 low longitudinal wings, smooth, glabrous; columella 1.1–1.3 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. |
whitish or grayish, subovoid, 1–1.6 × 0.6–1 mm, abaxial faces regularly large-pitted (appearing almost alveolate), adaxial faces longitudinally sulcate; caruncle deciduous, conic, 0.2–0.5 × 0.2–0.7 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 3–5, usually 2–8 times 2-branched, 1st branching level rarely 3-furcate; pleiochasial bracts similar in shape to and slightly larger than distal leaves; dichasial bracts distinct, ovate to obovate, base obtuse, margins entire, apex obtuse, usually mucronate; axillary cymose branches 0–3. |
Cyathia | peduncle 1–3 mm. |
peduncle 0.4–1.1 mm. |
2n | = 26. |
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Euphorbia chamaesula |
Euphorbia peplus |
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Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting year-round. |
Habitat | Clearings in ponderosa pine forests, montane roadsides, dry streambeds, creek banks, sandy and gravelly soils. | Edges of gardens, weedy flower beds, roadsides, waste places, open ground near forests. |
Elevation | 1700–2700 m. (5600–8900 ft.) | 0–1500 m. (0–4900 ft.) |
Distribution |
AZ; NM; Mexico (Chihuahua, Sonora)
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AL; AZ; CA; CO; CT; DE; IA; ID; IL; IN; KY; LA; MA; MD; ME; MI; MT; NC; ND; NH; NJ; NM; NV; NY; OH; OR; PA; RI; TN; TX; UT; VA; VT; WA; WI; WV; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK; Europe; w Asia [Introduced in North America; introduced also in Mexico, West Indies, Bermuda, Central America, South America, Africa, Atlantic Islands, Indian Ocean Islands, Pacific Islands, 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.) |
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Source | FNA vol. 12, p. 300. | FNA vol. 12, p. 307. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Tithymalus chamaesula | Esula peplus, Galarhoeus peplus, Tithymalus peplus |
Name authority | Boissier: Cent. Euphorb., 38. (1860) | Linnaeus: Sp. Pl. 1: 456. (1753) |
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