Euphorbia theriaca |
Euphorbia carunculata |
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Terlingua sandmat, Terlingua spurge |
sand-dune sandmat or spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, annual, with taproot. | ||||
Stems | prostrate to reclining, not mat-forming, 5–30 cm, glabrous. |
prostrate, spreading and lanky or occasionally mat-forming, ± succulent, 70–150 cm, glabrous. |
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Leaves | opposite; stipules usually distinct, occasionally connate basally on lower side of stem, subulate or scalelike, usually entire, occasionally 2-fid or margin sparsely ciliate, 0.4–1 mm, glabrous; petiole 0.7–1.2(–1.5) mm, glabrous; blade ovate, oblong, orbiculate, or obovate, 2–7.1 × 1–3.5 mm, base slightly asymmetric, rounded, margins entire, often revolute on drying, apex usually rounded, occasionally slightly emarginate, surfaces glabrous; venation usually obscure, only 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. |
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Involucre | usually turbinate-campanulate to hemispheric, occasionally suburceolate, 1–1.8 × 0.9–1.4 mm, glabrous; glands 4, yellow-green to red-purple, sessile or short-stipitate, subcircular to slightly elliptic, 0.2–0.5 × 0.2–0.7 mm; appendages absent or white to pink, semilunate or forming rim at edge of gland, (0–)0.1–0.4 × (0–)0.3–0.9 mm, entire or slightly crenate. |
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. |
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Staminate flowers | 15–36. |
15–25. |
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Pistillate flowers | ovary glabrous; styles 0.3–0.5 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.7–1 mm, 2-fid 1/2 length. |
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Capsules | broadly ovoid, 1.1–1.6 × 1.5–1.8 mm, glabrous; columella 1.2–1.5 mm. |
ovoid, 4.7–5.5(–6) × 3.6–5.1 mm, glabrous; columella 4.3–5.1 mm. |
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Seeds | whitish, reddish brown beneath coat, ovate, 4-angled in cross section, 0.8–1.2 × 0.5–0.8 mm, with (2–)3(–5) deep transverse ridges. |
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. |
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Cyathia | usually solitary at distal nodes, rarely clustered on short, axillary branches; peduncle 0.3–1.3 mm. |
solitary at distal nodes; peduncle 1.4–3.6 mm. |
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2n | = 28. |
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Euphorbia theriaca |
Euphorbia carunculata |
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Phenology | Flowering and fruiting summer–fall. | |||||
Habitat | Sand dunes. | |||||
Elevation | 400–1300 m. (1300–4300 ft.) | |||||
Distribution |
NM; TX; n Mexico
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KS; NM; OK; TX; Mexico (Chihuahua) |
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Discussion | Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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Key |
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Source | FNA vol. 12, p. 290. | FNA vol. 12, p. 262. | ||||
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Chamaesyce theriaca | Chamaesyce carunculata | ||||
Name authority | L. C. Wheeler: Rhodora 43: 242, plate 660, fig. A. (1941) | Waterfall: Rhodora 50: 63. (1948) | ||||
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