Euphorbia abramsiana |
Euphorbia pubentissima |
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Abrams' sandmat, Abrams' spurge |
false flowering spurge, southeastern flowering spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, perennial, with spreading rootstock. |
Stems | prostrate, mat-forming, 10–35(–50) cm, shortly pilose or puberulent at least proximally, often glabrous distally. |
erect, usually unbranched, occasionally few branched distally, solitary or few, previous year's dead stems not persistent, 30–65 cm, usually glabrous, rarely villous. |
Leaves | opposite; stipules distinct, divided into 5–7 subulate-filiform segments, 0.6–1.1 mm, usually glabrous, rarely pilose; petiole 0.5–1 mm, glabrous; blade ovate, elliptic-oblong, or slightly ovate-cordate, 3–11 × 2–5 mm, base asymmetric, truncate to hemicordate, margins serrulate at least toward apex, often entire toward base, apex acute to obtuse, surfaces sometimes with red spot in center, glabrous; usually only the midvein conspicuous. |
alternate; stipules 1 mm; petiole (0–)1–2(–10) mm, glabrous or densely villous; blade lanceolate, lance-ovate, elliptic, or obovate, 40–68 × 6–18 mm, often reflexed, base cuneate to rounded, margins entire, apex usually rounded, sometimes broadly acute, abaxial surface glabrous or villous, adaxial surface usually glabrous, rarely sparsely villous; venation occasionally obscure on small leaves, midvein conspicuous. |
Involucre | obconic, 0.5–0.6 × 0.4–0.5 mm, glabrous; glands 4, yellowish to pink, circular to oblong, 0.1 × 0.1–0.2 mm; appendages absent, or white to pink, semicircular to broadly ovate, to 0.1 × 0.2 mm, distal margin entire or shallowly lobed. |
campanulate or hemispheric, 1.3–1.7 × 1.8–2.2 mm, glabrous or villous; glands 5 (7–10 on central cyathium), green, reniform or broadly elliptic, 0.3–0.5 × 0.5–0.8 mm; appendages white, orbiculate or narrowly flabellate, 1–2.2 × 1.5 mm, entire. |
Staminate flowers | 3–5. |
20–25. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid nearly entire length. |
ovary glabrous or sparsely villous; styles 0.6–1.1 mm, 2-fid 1/2 length. |
Capsules | ellipsoid to ovoid, 1.3–1.5 × 1.1–1.5 mm, glabrous; columella 1–1.3 mm. |
globose, 2–2.4 × 3.3–4.8 mm, glabrous or sparsely villous; columella 1.8–2.1 mm. |
Seeds | light gray to light brown, narrowly ovoid to ovoid, 4-angled in cross section, 1–1.2 × 0.6–0.7 mm, with 3–5 prominent transverse ridges that often interrupt abaxial keel. |
light gray, ovoid, 2.2–2.4 × 1.6–1.8 mm, with shallow depressions; caruncle absent. |
Cyathia | solitary at distal nodes of primary stems or at nodes of short congested axillary branchlets; peduncle 0.2–0.5 mm. |
in terminal pleiochasia; peduncle 1–5 mm (or 15–40 mm on early flowering individuals), usually glabrous, occasionally sparsely villous. |
Euphorbia abramsiana |
Euphorbia pubentissima |
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Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting spring–fall. |
Habitat | Desert scrub and desert grasslands. | Open fields, cliffs, woods, floodplains. |
Elevation | -40–1400 m. (-100–4600 ft.) | 0–900 m. (0–3000 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Sonora)
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AL; FL; GA; LA; MD; MS; NC; SC; TN; VA; WV
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Discussion | The taxonomic history of Euphorbia pubentissima is complex. The species has been included within a very broadly defined E. corollata in the past. Therefore, its geographic distribution appears significantly more wide-ranging in some treatments. The framework established by M. J. Huft (1979) and later by K. R. Park (1998) is followed here. Euphorbia pubentissima is recognized as a variable species restricted to the southeastern United States. The species can be distinguished from E. corollata by its shorter involucral gland appendages and smaller seeds. Euphorbia paniculata Elliott, which sometimes is applied to E. pubentissima, is an illegitimate name (a later homonym of Euphorbia paniculata Desfontaines). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 259. | FNA vol. 12, p. 250. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Chamaesyce abramsiana | E. apocynifolia, E. corollata var. paniculata, E. corollata var. zinniiflora, E. zinniiflora, Tithymalopsis apocynifolia, T. paniculata, T. zinniiflora |
Name authority | L. C. Wheeler: Bull. S. Calif. Acad. Sci. 33: 109. (1934) | Michaux: Fl. Bor.-Amer. 2: 212. (1803) |
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