Euphorbia abramsiana |
Euphorbia carunculata |
|
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Abrams' sandmat, Abrams' spurge |
sand-dune sandmat or spurge |
|
Habit | Herbs, annual, with slender taproot. | Herbs, annual, with taproot. |
Stems | prostrate, mat-forming, 10–35(–50) cm, shortly pilose or puberulent at least proximally, often glabrous distally. |
prostrate, spreading and lanky or occasionally mat-forming, ± succulent, 70–150 cm, glabrous. |
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 usually distinct, occasionally connate basally (primarily at distal nodes), usually divided into 2–5 subulate to subulate-filiform segments, occasionally forming narrow deltate segments (primarily at distal nodes), 0.8–1.8 mm, glabrous; petiole 3.1–6.3 mm, glabrous; blade ovate to elliptic-oblong, 5–26 × 4–12 mm, base subsymmetric to symmetric, rounded to cuneate, margins entire, apex usually mucronate, rarely acute or obtuse, surfaces glabrous; pinnately veined. |
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, 1.1–1.8 × 1.5–2.5 mm, glabrous; glands 4, yellowish, sessile or short stipitate, circular to oblong, 0.5–0.7 × 0.5–0.8 mm; appendages white to yellowish, ovate to oblong, occasionally rudimentary, (0–)0.8–1.2 × 0.8–1.5 mm, distal margin entire. |
Staminate flowers | 3–5. |
15–25. |
Pistillate flowers | ovary glabrous; styles 0.1–0.3 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.7–1 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. |
ovoid, 4.7–5.5(–6) × 3.6–5.1 mm, glabrous; columella 4.3–5.1 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. |
grayish white to reddish brown mottled, bottle-shaped, strongly dorsiventrally compressed and weakly 3-angled in cross section, (2.8–)4.1–5.2 × 1.2–2(–3.4) mm, smooth; carunclelike structure linear, 0.4–0.5 × 0.1–0.2 mm. |
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 1.4–3.6 mm. |
Euphorbia abramsiana |
Euphorbia carunculata |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting summer–fall. |
Habitat | Desert scrub and desert grasslands. | Sand dunes. |
Elevation | -40–1400 m. (-100–4600 ft.) | 400–1300 m. (1300–4300 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Sonora)
|
KS; NM; OK; TX; Mexico (Chihuahua) |
Discussion | Euphorbia carunculata has a highly localized and scattered distribution. The species is restricted to sand dunes and known from only a handful of localities throughout its relatively wide range. The seeds are unique in being bottle-shaped and strongly laterally compressed, and unlike other members of sect. Anisophyllum, there is a minute, linear, carunclelike protuberance at the hilum. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 259. | FNA vol. 12, p. 262. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce abramsiana | Chamaesyce carunculata |
Name authority | L. C. Wheeler: Bull. S. Calif. Acad. Sci. 33: 109. (1934) | Waterfall: Rhodora 50: 63. (1948) |
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