Euphorbia thymifolia |
Euphorbia innocua |
|
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gulf sandmat |
velvet spurge |
|
Habit | Herbs, annual or perennial, with taproot. | Herbs, perennial, with moderately to strongly thickened rootstock. |
Stems | prostrate, mat-forming, 15–30 cm, strigose to strigose-tomentulose. |
prostrate to decumbent or ascending, branched (often near base), 7–45 cm, densely pilose. |
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. |
alternate; stipules to 0.1 mm; petiole (0.7–)1.1–3.5 mm, pilose; blade ovate to orbiculate, 4.6–17(–25) × 4.5–15(–19) mm, base cordate, margins entire, apex rounded to obtuse, surfaces densely pilose; venation obscure, usually only midvein conspicuous. |
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, 1–1.3 × 1.2–1.4 mm, pilose; glands 4, yellow to green, elliptic, 0.2–0.3 × 0.5–0.6 mm; appendages green, elliptic, 0.4–0.5 × 0.5–0.9 mm, entire or crenulate, ciliate. |
Staminate flowers | 3–5. |
5–10. |
Pistillate flowers | ovary densely strigose; styles 0.4–0.5 mm, 2-fid 1/2 length. |
ovary pilose; styles 0.4–0.7 mm, 2-fid 1/2 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. |
depressed-ovoid, 2–2.5 × 2.7–3.3 mm, pilose; columella 1.6–2.1 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 to brown, ovoid, 1.5–1.7 × 1.2–1.3 mm, rugose with whitish ridges; caruncle absent. |
Cyathia | usually in small, cymose clusters on congested, axillary branches; peduncle (0–)0.1–0.3 mm. |
in terminal dichasia (often weakly defined); peduncle 1–2.7 mm, densely pilose. |
Euphorbia thymifolia |
Euphorbia innocua |
|
Phenology | Flowering and fruiting midsummer–early fall. | Flowering and fruiting early winter–late spring. |
Habitat | Disturbed areas, often near salt water. | Sandy soils or dunes, grasslands, pastures. |
Elevation | 0–20 m. (0–100 ft.) | 0–20 m. (0–100 ft.) |
Distribution |
FL; LA; Mexico; South America; West Indies [Introduced in Asia, tropical Africa, Australia] |
TX |
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.) |
Euphorbia innocua is restricted to south coastal Texas in Aransas, Calhoun, Kenedy, Kleberg, Nueces, Refugio, San Patricio, and Willacy counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 291. | FNA vol. 12, p. 247. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Chamaesyce thymifolia | |
Name authority | Linnaeus: Sp. Pl. 1: 454. (1753) | L. C. Wheeler: Contr. Gray Herb. 127: 62, plate 3, fig. D. (1939) |
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