Euphorbia florida |
Euphorbia chamaesula |
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Chiricahua Mountain sandmat |
mountain spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, perennial, with thick rootstock. |
Stems | erect, 15–60 cm, usually glabrous, rarely puberulent. |
erect, branched, 40–90 cm, glabrous. |
Leaves | opposite; stipules distinct, divided into 3–4 subulate-filiform divisions, 0.4–1.6 mm, usually glabrous, rarely puberulent; petiole 0.5–2.5 mm, glabrous; blade usually linear, rarely to narrowly elliptic, 10–40(–60) × 0.5–2.5 mm, base symmetric, attenuate, margins serrulate, often revolute, apex acute, surfaces usually glabrous, rarely puberulent; obscurely pinnately veined. |
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. |
Involucre | obconic, 1.7–2.4 × 1.5–2.1 mm, glabrous; glands 4, greenish yellow to slightly pink, circular to oblong, 0.4–0.5 × 0.4–0.6 mm; appendages white to pink, obovoid, circular, flabellate, or oblong, 0.8–2.9 × 1–2.8 mm, distal margin entire. |
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. |
Staminate flowers | 25–35. |
8–12. |
Pistillate flowers | ovary glabrous; styles 0.8–1.4 mm, 2-fid entire length. |
ovary glabrous; styles 1–1.8 mm, 2-fid. |
Capsules | oblate, 2.2–2.5 × 2.7–3.1 mm, glabrous; columella 1.8–2.1 mm. |
depressed-ovoid, 4.3–5 × 5–6 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 3.5–4 mm. |
Seeds | light gray to light brown, ovoid, slightly 4-angled in cross section, 1.6–2 × 1.3–1.7 mm, with 2 or 3 well-developed transverse ridges. |
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. |
Cyathia | solitary at nodes or in small, cymose clusters at branch tips; peduncle 1.2–8.1 mm. |
peduncle 1–3 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. |
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2n | = 26. |
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Euphorbia florida |
Euphorbia chamaesula |
|
Phenology | Flowering and fruiting summer–late fall. | Flowering and fruiting spring–summer. |
Habitat | Sandy flats, gravelly washes, rocky hillsides, talus slopes, desert scrub, desert grasslands, mesquite woodlands, rarely oak woodlands. | Clearings in ponderosa pine forests, montane roadsides, dry streambeds, creek banks, sandy and gravelly soils. |
Elevation | 600–1300 m. (2000–4300 ft.) | 1700–2700 m. (5600–8900 ft.) |
Distribution |
AZ; Mexico (Sinaloa, Sonora)
|
AZ; NM; Mexico (Chihuahua, Sonora)
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Discussion | Euphorbia florida is known in the flora area from Coconino County south to the Mexican border (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 12, p. 267. | FNA vol. 12, p. 300. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Chamaesyce florida | Tithymalus chamaesula |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) | Boissier: Cent. Euphorb., 38. (1860) |
Web links |