Euphorbia thymifolia |
Euphorbia peplidion |
|
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gulf sandmat |
low spurge |
|
Habit | Herbs, annual or perennial, with taproot. | Herbs, annual, with taproot. |
Stems | prostrate, mat-forming, 15–30 cm, strigose to strigose-tomentulose. |
erect, unbranched or branched, 5–20 cm, glabrous. |
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. |
petiole 0–0.2 mm; blade linear-oblanceolate to cuneate-spatulate, 5–20 × 1–4 mm, base attenuate, margins entire, apex rounded to obtuse, surfaces glabrous; venation inconspicuously 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. |
broadly campanulate-turbinate, 0.8–1 × 0.6–0.9 mm, glabrous; glands 4, elliptic, 0.2–0.3 × 0.5–0.6 mm; horns divergent, 0.4–0.5 mm. |
Staminate flowers | 3–5. |
5–10. |
Pistillate flowers | ovary densely strigose; styles 0.4–0.5 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.5–0.7 mm, 2-fid. |
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-globose, 1.8–2.3 × 2.6–3 mm, 3-lobed; cocci slightly flattened, without wings, smooth, glabrous; columella 1.3–1.5 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, oblong, 1.3–1.6 × 0.9–1.1 mm, abaxial faces irregularly large-pitted, adaxial faces longitudinally sulcate; caruncle flat, umbonate, 2-lobed, 0.4 × 0.7 mm. |
Cyathia | usually in small, cymose clusters on congested, axillary branches; peduncle (0–)0.1–0.3 mm. |
peduncle 0.3–0.5 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3(–5), 1–3 times 2-branched; pleiochasial bracts linear, lanceolate, or spatulate, similar in size to distal leaves; dichasial bracts distinct, rhomboid-lanceolate to ovate, falcate, base rounded to obtuse, margins entire or slightly erose, apex acute; axillary cymose branches 0–3. |
|
Euphorbia thymifolia |
Euphorbia peplidion |
|
Phenology | Flowering and fruiting midsummer–early fall. | Flowering and fruiting late winter–spring. |
Habitat | Disturbed areas, often near salt water. | Dry, sandy areas, open areas with poor soils, roadsides, stream banks. |
Elevation | 0–20 m. (0–100 ft.) | 100–300 m. (300–1000 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 peplidion is native to central and south-central Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 291. | FNA vol. 12, p. 306. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Chamaesyce thymifolia | Tithymalus peplidion |
Name authority | Linnaeus: Sp. Pl. 1: 454. (1753) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 191. (1859) |
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