Euphorbia ophthalmica |
Euphorbia schizoloba |
|
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Florida hammock sandmat |
Mojave spurge |
|
Habit | Herbs, usually annual, rarely short-lived perennial, with slender to slightly thickened taproot. | Herbs, perennial, with thick rootstock. |
Stems | usually prostrate, rarely ascending, 6–22 cm, usually both strigillose and hirsute. |
slender, ascending, often sinuous, many, densely branched near base, 10–50 cm, usually glabrous, usually glaucous. |
Leaves | 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. |
petiole 0–1 mm; blade broadly oblanceolate to obovate, 10–20 × 3–9 mm, base usually acute, occasionally short-attenuate, rarely obtuse, margins entire, apex usually acute, occasionally obtuse, acuminate to cuspidate, surfaces usually glabrous, usually glaucous; venation pinnate, sometimes obscure, midvein prominent. |
Involucre | 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. |
campanulate to broadly turbinate, 2.2–3 × 2–2.5 mm, glabrous; glands 4, irregularly semicircular to trapezoidal or elliptic-truncate, 0.8–1.5 × 1–2.2, margins strongly crenate or dentate; horns usually absent, if present then straight, 0.1–0.2 mm, generally equaling teeth on gland margin. |
Staminate flowers | 2–8. |
12–20. |
Pistillate flowers | ovary strigillose, often canescent when young; styles 0.1–0.3 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous; styles 1–1.2 mm, 2-fid. |
Capsules | ovoid, 1–1.2 × 1–1.3 mm, strigillose; columella 0.7–1.1 mm. |
oblong-ovoid, 3.5–4 × 3.8–5 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 3.3–3.8 mm. |
Seeds | 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. |
gray to whitish, oblong cylindric, 2–3 × 1.5 mm, irregularly shallowly pitted to almost smooth; caruncle conic, 0.6 × 0.6 mm. |
Cyathia | in dense, terminal, capitate glomerules, with reduced, bractlike leaves subtending cyathia; peduncles 0–0.8 mm. |
peduncle 0.3–1 mm. |
Cyathial | arrangement: terminal pleiochasial branches (1–)3–4(–5), each 1–3 times 2-branched; pleiochasial bracts broadly ovate to subcordate, usually similar in size to, occasionally wider than, distal leaves; dichasial bracts distinct, broadly ovate to almost reniform, base obtuse, margins entire, apex obtuse, acuminate to cuspidate; axillary cymose branches 0–2(–4). |
|
Euphorbia ophthalmica |
Euphorbia schizoloba |
|
Phenology | Flowering and fruiting year-round. | Flowering and fruiting spring–summer. |
Habitat | Hammock forests, disturbed areas in lawns, roadsides. | Desert mountains and canyon slopes, rocky and gravelly soils. |
Elevation | 0–200 m. (0–700 ft.) | 500–1800 m. (1600–5900 ft.) |
Distribution |
AR; CA; FL; GA; LA; MO; PA; Mexico; Central America; South America; West Indies [Introduced in Europe] |
AZ; CA; NV
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Discussion | 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.) |
Euphorbia schizoloba is a desert perennial that occurs on bluffs and ledges in the Mojave and Sonoran Deserts. Sparsely pubescent plants of E. schizoloba are known from Arizona and are best represented by several collections from the Mazatzal and Sierra Ancha mountains in Gila County from between 1000 to 1800 meters. George Engelmann published two names for this species almost simultaneously in 1861 (E. schizoloba and E. incisa). Although the authors have not been able to determine which publication has priority, Engelmann himself cited E. incisa as a synonym of E. schizoloba (in W. H. Brewer et al. 1876–1880, vol. 2), as did J. B. S. Norton (1899). Also, the type specimen at MO was annotated by Engelmann as E. schizoloba, and there is no mention of the name E. incisa on the sheet. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 280. | FNA vol. 12, p. 309. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Chamaesyce ophthalmica, E. hirta var. procumbens, E. pilulifera var. procumbens | E. incisa, Tithymalus incisus, T. schizolobus |
Name authority | Persoon: Syn. Pl. 2: 13. (1806) | Engelmann: Proc. Amer. Acad. Arts 5: 173. (1861) |
Web links |