Euphorbia thymifolia |
Euphorbia cuphosperma |
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gulf sandmat |
hairy-fruit spurge |
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Habit | Herbs, annual or perennial, with taproot. | Herbs, annual, with taproot. |
Stems | prostrate, mat-forming, 15–30 cm, strigose to strigose-tomentulose. |
erect, 13–20 cm, both pilose to villous and densely strigillose; branches ± straight. |
Leaves | opposite; stipules distinct or slightly connate at base, linear-subulate, entire or slightly parted, 0.9–1.2 mm, strigose-tomentulose; petiole 0.5–1 mm, sparsely strigose-tomentulose; blade broadly elliptic to narrowly oblong or ovate-lanceolate, 3–10 × 1.8–5 mm, base asymmetric, one side usually angled or rounded and the other truncate and expanded into small, rounded auricle, margins serrate (larger leaves) to serrulate (smaller leaves), apex blunt to acute, abaxial surface sparsely tomentulose to glabrate, adaxial surface glabrate; palmately veined at base, pinnate distally. |
usually opposite, occasionally alternate at distal nodes; petiole 3–15 mm, pilose; blade narrowly to broadly elliptic, or lanceolate to ovate, 30–80 × 10–15 mm, base cuneate to rounded, margins coarsely crenate-dentate, strigose, revolute to nearly flat, apex broadly acute to acuminate, or obtuse, abaxial surface pilose, adaxial surface sparsely strigose-hirsute; venation pinnate, midvein prominent. |
Involucre | broadly obconic, becoming distended and distorted by base of partially included capsule, 0.4–0.8 × 0.3–0.5 mm, strigose; glands 4, red, slightly concave, ± unequal, subcircular to broadly oval, 0.1–0.2 × 0.2–0.3 mm; appendages white to pink, usually unequal, occasionally ± equal at distal nodes, elongated toward sinus, sometimes rudimentary, 0.1–0.4 × 0.1–0.3 mm, distal margin entire or crenulate. |
campanulate to slightly cylindric, 2.3 × 1.2 mm, glabrous; involucral lobes divided into several linear, smooth lobes; gland 1, yellow-green, stipitate, clavate, 1–1.2 × 0.8–0.9 mm, opening bilabiate and oblong, glabrous; appendages absent. |
Staminate flowers | 3–5. |
3–5. |
Pistillate flowers | ovary densely strigose; styles 0.4–0.5 mm, 2-fid 1/2 length. |
ovary pilose; styles 1.2 mm, 2-fid nearly entire length. |
Capsules | conic to truncate-ovoid, scarcely exserted from involucre, base often remaining inside involucre and splitting one side of it during maturation, 0.9–1.2 × 1–1.2 mm, sparsely to moderately strigose; columella 0.6–1 mm. |
broadly ovoid, 2.2–3 × 1.9–2.7 mm, 3-lobed, pilose; columella 2–2.4 mm. |
Seeds | white, tan underneath coat, ovoid to narrowly ovoid, sharply 4-angled in cross section, 0.8–0.9 × 0.4–0.6 mm, with 4 low transverse ridges often slightly extending into angles, not sulcate. |
gray-brown to pale gray, pyramidally ovoid, angular in cross section, 2.3–2.6 × 2.4–2.6 mm, coarsely tuberculate, tubercles in 2 transverse rows; caruncle 0.2–0.4 mm. |
Cyathia | usually in small, cymose clusters on congested, axillary branches; peduncle (0–)0.1–0.3 mm. |
peduncle 0.5–0.8 mm. |
Cyathial | arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched; pleiochasial bracts 2–4, often whorled, wholly green or paler green at base, similar in shape and size to distal leaves or slightly narrower; dichasial bracts highly reduced. |
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2n | = 56. |
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Euphorbia thymifolia |
Euphorbia cuphosperma |
|
Phenology | Flowering and fruiting midsummer–early fall. | Flowering and fruiting summer–fall. |
Habitat | Disturbed areas, often near salt water. | Open montane and canyon forests, pinyon-juniper forests, montane grasslands, stream beds, disturbed habitats. |
Elevation | 0–20 m. (0–100 ft.) | 800–2000 m. (2600–6600 ft.) |
Distribution |
FL; LA; Mexico; South America; West Indies [Introduced in Asia, tropical Africa, Australia] |
AZ; NM; Mexico; Central America (Guatemala)
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Discussion | Euphorbia thymifolia is a widespread tropical and subtropical weed. It is not certain where the species is native, but most likely it originated in the New World and then became widespread in the rest of the tropics. Euphorbia thymifolia is present in the flora area in southern Florida and coastal Louisiana, where it is likely adventive. Euphorbia thymifolia is generally similar to E. maculata but is characterized by its short pistillate pedicels and non-exserted capsules that remain largely enclosed by the involucre and by its unequal involucral gland appendages. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 291. | FNA vol. 12, p. 319. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Poinsettia |
Sibling taxa | ||
Synonyms | Chamaesyce thymifolia | E. dentata var. cuphosperma, Poinsettia cuphosperma |
Name authority | Linnaeus: Sp. Pl. 1: 454. (1753) | (Engelmann) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 73. (1862) |
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