Euphorbia thymifolia |
Euphorbia nephradenia |
|
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gulf sandmat |
Paria spurge, Utah spurge |
|
Habit | Herbs, annual or perennial, with taproot. | Herbs, annual, with slender little-branched taproot. |
Stems | prostrate, mat-forming, 15–30 cm, strigose to strigose-tomentulose. |
erect to ascending, branched, dichotomous distally and slightly angled, 4–25 cm, glabrous or sparsely strigillose. |
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. |
opposite; stipules 0.1–0.2 mm; petiole 2–6 mm, glabrous or sparsely strigillose; blade usually linear- to narrowly-elliptic, occasionally ovate to obovate, 14–42 × 3–10 mm, progressively narrower distally, base attenuate, margins entire, apex usually acute, rarely obtuse, surfaces glabrous or sparsely strigillose; venation inconspicuous. |
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, 1–1.1 × 1.2–1.4 mm, strigillose at least toward apex; glands 5, green-yellow, oblong, 0.4–0.6 × 0.7–1 mm; appendages whitish to yellow-green, lunate to broadly ovate, 0.2–0.5 × 0.7–1.1 mm, entire or slightly crenulate. |
Staminate flowers | 3–5. |
25–30. |
Pistillate flowers | ovary densely strigose; styles 0.4–0.5 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.7–1 mm, 2-fid at apex. |
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. |
oblate to subglobose, 2.9–3.2 × 3.2–3.4 mm, glabrous; columella 2.8–3.1 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. |
light gray to whitish, oblong-ovoid, rounded in cross section, 2.3–2.6 × 1.3–1.5 mm, dimpled and rugulose; caruncle absent. |
Cyathia | usually in small, cymose clusters on congested, axillary branches; peduncle (0–)0.1–0.3 mm. |
solitary at distal bifurcations of stems; peduncle 0.6–2.4 mm, glabrous or strigillose. |
Euphorbia thymifolia |
Euphorbia nephradenia |
|
Phenology | Flowering and fruiting midsummer–early fall. | Flowering and fruiting spring–summer. |
Habitat | Disturbed areas, often near salt water. | Saltbush, blackbrush, Ephedra-dominated scrub and desert communities. |
Elevation | 0–20 m. (0–100 ft.) | 1100–1500 m. (3600–4900 ft.) |
Distribution |
FL; LA; Mexico; South America; West Indies [Introduced in Asia, tropical Africa, Australia] |
CO; UT |
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 nephradenia is the only species of the genus endemic to the Colorado Plateau of Utah and adjacent Colorado. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 291. | FNA vol. 12, p. 249. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Chamaesyce thymifolia | |
Name authority | Linnaeus: Sp. Pl. 1: 454. (1753) | Barneby: Leafl. W. Bot. 10: 314. (1966) |
Web links |