Euphorbia abramsiana |
Euphorbia lata |
|
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Abrams' sandmat, Abrams' spurge |
broadleaf spurge, hoary sandmat |
|
Habit | Herbs, annual, with slender taproot. | Herbs, perennial, with moderately thickened to robust rootstock. |
Stems | prostrate, mat-forming, 10–35(–50) cm, shortly pilose or puberulent at least proximally, often glabrous distally. |
ascending to erect, or prostrate, 10–25 cm, strigose to short-sericeous or ± 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. |
opposite; stipules distinct, filiform, 0.8–1.3 mm, strigose to short-sericeous or ± villous; petiole 0.5–2 mm, densely strigose to short-sericeous or ± villous; blade narrowly to broadly ovate-deltate, older ones often falcate, 4–12 × 3–7 mm, base asymmetric, obliquely rounded to obtuse, noticeably wider on one side, margins entire, often ± revolute, apex broadly acute, surfaces strigose to short-sericeous or ± villous; obscurely 3–5-veined from base, midvein prominent abaxially. |
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. |
broadly campanulate, 2–2.5 × 2.2–2.6, strigose; glands 4, greenish, oblong to semilunate, 0.2–0.7 × 0.6–1 mm; appendages rudimentary or white, forming narrow band, (0–)0.1–0.2 × (0–)0.6–1 mm, distal margin entire or crenate. |
Staminate flowers | 3–5. |
25–35. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid nearly entire length. |
ovary densely strigose to short-sericeous or ± villous; styles dark purplish, 0.8–1.2 mm, 2-fid 1/2 to nearly entire length. |
Capsules | ellipsoid to ovoid, 1.3–1.5 × 1.1–1.5 mm, glabrous; columella 1–1.3 mm. |
ovoid, 1.9–2.3 × 2–2.4 mm, strigose to short-sericeous or ± villous; columella 1.7–2.2 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. |
whitish, oblong, 4-angled in cross section, faces concave, 1.5–1.8(–2) × 0.6–0.9 mm, smooth. |
Cyathia | solitary at distal nodes of primary stems or at nodes of short congested axillary branchlets; peduncle 0.2–0.5 mm. |
solitary at distal nodes; peduncle 1–3 mm. |
2n | = 28, 56. |
|
Euphorbia abramsiana |
Euphorbia lata |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting spring–fall. |
Habitat | Desert scrub and desert grasslands. | Mountain slopes, canyons, basins, rocky prairies, roadsides, disturbed sites, usually in calcareous soils, sometimes in igneous-derived, sandy or rocky soils. |
Elevation | -40–1400 m. (-100–4600 ft.) | 600–2200 m. (2000–7200 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Sonora)
|
CO; KS; NM; OK; TX; Mexico (Chihuahua, Coahuila)
|
Source | FNA vol. 12, p. 259. | FNA vol. 12, p. 275. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce abramsiana | E. dilatata, Chamaesyce lata, E. rinconis |
Name authority | L. C. Wheeler: Bull. S. Calif. Acad. Sci. 33: 109. (1934) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 188. (1859) |
Web links |