Euphorbia chamaesula |
Euphorbia ophthalmica |
|
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mountain spurge |
Florida hammock sandmat |
|
Habit | Herbs, perennial, with thick rootstock. | Herbs, usually annual, rarely short-lived perennial, with slender to slightly thickened taproot. |
Stems | erect, branched, 40–90 cm, glabrous. |
usually prostrate, rarely ascending, 6–22 cm, usually both strigillose and hirsute. |
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; stipules distinct, subulate-filiform, undivided or divided into 2–4 narrowly triangular to linear-subulate segments, no dark, circular glands at base of stipules, 0.9–1.5 mm, pilose or strigillose; petiole 0.3–1.2 mm, glabrescent, strigillose, or sericeous; blade usually ovate or oblong, rarely subrhombic, 4–13 × 3–7 mm, base asymmetric, one side usually angled and other side rounded, margins coarsely serrulate, apex acute, surfaces often with red spot in center, strigillose or sericeous, or adaxial surface glabrescent; 3-veined from base. |
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. |
obconic, 0.5–0.7 × 0.4–0.6 mm, strigillose; glands 4, yellow green to pink, circular to slightly oblong, 0.1–0.2 × 0.1–0.2 mm; appendages absent or white to pink, forming thin rim around edge of gland or oblong, 0.1–0.2 × 0.1–0.3 mm, distal margin entire or shallowly lobed. |
Staminate flowers | 8–12. |
2–8. |
Pistillate flowers | ovary glabrous; styles 1–1.8 mm, 2-fid. |
ovary strigillose, often canescent when young; styles 0.1–0.3 mm, 2-fid 1/2 to nearly entire length. |
Capsules | depressed-ovoid, 4.3–5 × 5–6 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 3.5–4 mm. |
ovoid, 1–1.2 × 1–1.3 mm, strigillose; columella 0.7–1.1 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. |
orange-brown to pinkish, narrowly ovoid, 4-angled in cross section, 0.7–0.9(–1.1) × 0.5 mm, usually rugulose, with 3–6 faint, low, transverse ridges, rarely almost smooth. |
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. |
|
Cyathia | peduncle 1–3 mm. |
in dense, terminal, capitate glomerules, with reduced, bractlike leaves subtending cyathia; peduncles 0–0.8 mm. |
2n | = 26. |
|
Euphorbia chamaesula |
Euphorbia ophthalmica |
|
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. | Hammock forests, disturbed areas in lawns, roadsides. |
Elevation | 1700–2700 m. (5600–8900 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
AZ; NM; Mexico (Chihuahua, Sonora)
|
AR; CA; FL; GA; LA; MO; PA; Mexico; Central America; South America; West Indies [Introduced in Europe] |
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 ophthalmica is a weedy species distributed throughout the Neotropics. It is also adventive in the Old World. Whether it is indeed native to the southeastern United States is questionable; it is introduced in Arkansas, California, Missouri, and Pennsylvania and likely occurs also in other states. Although sometimes treated as E. hirta var. procumbens, E. ophthalmica appears sufficiently distinct to justify recognition at the rank of species, differing primarily by its mostly prostrate growth form, smaller leaves, and strictly terminal clusters of cyathia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 300. | FNA vol. 12, p. 280. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus chamaesula | Chamaesyce ophthalmica, E. hirta var. procumbens, E. pilulifera var. procumbens |
Name authority | Boissier: Cent. Euphorb., 38. (1860) | Persoon: Syn. Pl. 2: 13. (1806) |
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