Euphorbia theriaca |
Euphorbia cumulicola |
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Terlingua sandmat, Terlingua spurge |
coastal dune sandmat |
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Habit | Herbs, annual, with slender taproot. | Herbs, usually annual, rarely perennial, with taproot. | ||||
Stems | prostrate to reclining, not mat-forming, 5–30 cm, glabrous. |
prostrate, 10–20 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 distinct, linear-subulate, usually divided into 3–7 linear segments, 0.5–1 mm, glabrous; petiole 0.5–1 mm, glabrous; blade narrowly elliptic to lanceolate, 4–8 × 1–2 mm uniform in size, base asymmetric, obtuse to rounded, margins entire, apex obtuse to acute, surfaces green to reddish flushed, glabrous; only midvein conspicuous. |
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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, 0.9–1.1 × 1–1.3 mm, glabrous; glands 4, green to red, slightly stipitate, subcircular, 0.1 × 0.1 mm; appendages white or pink, fringing edge of gland, short-flabellate, often rudimentary, 0.1–0.2 × 0.1 mm, distal margin crenate or entire. |
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Staminate flowers | 15–36. |
5–8. |
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Pistillate flowers | ovary glabrous; styles 0.3–0.5 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.2–0.3 mm, 2-fid at apex to nearly 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 or subglobose, 1.8–2 × 2–2.3 mm, glabrous; columella 1.2–1.5 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. |
white to gray-brown, ovoid, terete to bluntly subangled in cross section, 1–1.3 × 1 mm, smooth or minutely pitted, with smooth brown line from top to bottom on adaxial side. |
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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 mm. |
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2n | = 28. |
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Euphorbia theriaca |
Euphorbia cumulicola |
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Phenology | Flowering and fruiting year-round. | |||||
Habitat | Sandy oak hammocks, open sandy areas behind mangroves, disturbed sandy sites. | |||||
Elevation | 0–10 m. (0–0 ft.) | |||||
Distribution |
NM; TX; n Mexico
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FL |
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Discussion | Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia cumulicola could be confused with E. bombensis, both of which are widespread in Florida, but there the latter occurs on beaches close to the ocean, whereas E. cumulicola is not a beach-inhabiting species but occurs in more protected sandy habitats such as hammocks or stabilized dunes behind mangroves. Also, E. bombensis has fleshier leaves and larger seeds, and is more compact in habit than E. cumulicola, which is a more sprawling and densely branched plant with leaves that are usually purplish tinged along the margins. (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. 265. | ||||
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Chamaesyce theriaca | Chamaesyce cumulicola | ||||
Name authority | L. C. Wheeler: Rhodora 43: 242, plate 660, fig. A. (1941) | (Small) Oudejans: Phytologia 67: 45. (1989) | ||||
Web links |