Euphorbia bicolor |
Euphorbia florida |
|
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snow-on-the-prairie |
Chiricahua Mountain sandmat |
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Habit | Herbs, annual, with taproot. | Herbs, annual, with slender taproot. |
Stems | erect, unbranched or branched, 40–100 cm, pilose. |
erect, 15–60 cm, usually glabrous, rarely puberulent. |
Leaves | alternate; stipules 0.3–0.4 mm; petiole 0.3–1 mm, pilose; blade narrowly elliptic to lanceolate, 37–54 × 7–17 mm, base cuneate to slightly rounded, margins entire, apex aristate or acute, surfaces pilose; venation obscure, only midvein conspicuous. |
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. |
Involucre | campanulate, 2.7–3.5 × 2.2–3 mm, densely pilose; glands 4–5, green to pale greenish yellow, reniform, 0.6–0.7 × 1.4–1.6 mm; appendages white, obdeltate to orbiculate, 1.4–2.5 × 1.7–3 mm, dentate to erose. |
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. |
Staminate flowers | 30–70. |
25–35. |
Pistillate flowers | ovary pilose; styles 0.7–1.2 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.8–1.4 mm, 2-fid entire length. |
Capsules | depressed-ovoid, 3.5–7.5 × 6–8.7 mm, densely pilose; columella 4.5–5.5 mm. |
oblate, 2.2–2.5 × 2.7–3.1 mm, glabrous; columella 1.8–2.1 mm. |
Seeds | tan to brown, ovoid, 4.3–4.5 × 3.7–3.9 mm, alveolate; caruncle absent. |
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. |
Cyathia | in terminal pleiochasia dichasial and pleiochasial bracts linear to narrowly oblanceolate, with conspicuous white margins; peduncle 1.2–3 mm, densely pilose. |
solitary at nodes or in small, cymose clusters at branch tips; peduncle 1.2–8.1 mm. |
Euphorbia bicolor |
Euphorbia florida |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting summer–late fall. |
Habitat | Prairies, blackland (calcareous) prairies, pastures and clearings in former blackland prairie areas, roadside clearings. | Sandy flats, gravelly washes, rocky hillsides, talus slopes, desert scrub, desert grasslands, mesquite woodlands, rarely oak woodlands. |
Elevation | 100–200 m. (300–700 ft.) | 600–1300 m. (2000–4300 ft.) |
Distribution |
AR; LA; OK; TX
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AZ; Mexico (Sinaloa, Sonora)
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Discussion | Euphorbia bicolor is similar in appearance to E. marginata but can be distinguished by its linear to narrowly oblanceolate bracts and the presence of hairs on all parts of the plant. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 12, p. 243. | FNA vol. 12, p. 267. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce florida | |
Name authority | Engelmann & A. Gray: Boston J. Nat. Hist. 5: 233. (1845) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) |
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