Euphorbia oblongata |
Euphorbia trachysperma |
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Balkan spurge, egg-leaf spurge, oblong spurge |
San Pedro River sandmat |
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Habit | Herbs, perennial, with woody taproot. | Herbs, annual, with slender taproot. |
Stems | erect, unbranched or densely branching, 80 cm, often densely villous (especially young stems and pleiochasial branches). |
erect to ascending, 10–55 cm, glabrous. |
Leaves | petiole absent; blade oblong to narrowly obovate or lanceolate, 15–70 × 6–25 mm, base rounded or truncate, margins finely serrulate, apex obtuse, mucronulate, surfaces glabrous; venation inconspicuously pinnate, midvein prominent. |
opposite; stipules distinct, narrowly triangular and often divided into 3–5 subulate to filiform segments, 0.8–1.9 mm, glabrous; petiole 1.2–3.1 mm, glabrous; blade oblong, elliptic, or ovate, 12–43 × 3–14 mm, base subsymmetric to asymmetric, rounded, attenuate, or with one side hemicordate and other side rounded, margins usually serrulate, rarely entire on some leaves or portion of blade, apex obtuse to acute, surfaces often with red blotch in center, glabrous; pinnately veined, often only midvein conspicuous. |
Involucre | cupulate to slightly turbinate, 1.5–2.5 × 1.3–1.5 mm, glabrous; glands 2–3, elliptic, 0.6–0.8 × 0.8–1.2 mm; horns absent. |
oblong, campanulate, or funnel-shaped, 1.5–2.6 × 1.1–2.3 mm, glabrous; glands 4, green to yellowish or tinged with red, subcircular to oblong, 0.4–0.7 × 0.5–1 mm; appendages absent or white, often forming narrow rim or oblong to ovate, 0–0.8 × 1.2 mm, distal margin entire. |
Staminate flowers | 15–40. |
50–60. |
Pistillate flowers | ovary glabrous; styles 1.5–2 mm, 2-fid. |
ovary glabrous; styles 0.5–0.6 mm, 2-fid 1/2 length. |
Capsules | globose, 3–4.5 × 3–4.5 mm, slightly 3-lobed; cocci rounded, verrucose-tuberculate, glabrous; columella 2.5–3.3 mm. |
oblate, 2.4–3.2 × 3–3.5 mm, glabrous; columella 2.3–2.5 mm. |
Seeds | brown, ovoid, 2.4–2.6 × 1.3–2 mm, smooth, caruncle reniform, 0.2–0.3 × 0.8–0.9 mm. |
light brown, ovoid, 4-angled in cross section, abaxial keel well developed, 1.9–2.3 × 1.3–1.4 mm, finely dimpled and papillate. |
Cyathial | arrangement: terminal pleiochasial branches 3–5, each 2–3 times 2–4-branched; pleiochasial bracts ovate, similar in size to distal leaves; dichasial bracts distinct, ovate to suborbiculate, base truncate or rounded, margins entire or finely denticulate, apex obtuse, sometimes mucronulate; axillary cymose branches 0–4. |
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Cyathia | peduncle 1–5 mm. |
solitary at distal nodes; peduncle 1.4–2.4 mm. |
Euphorbia oblongata |
Euphorbia trachysperma |
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Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting late summer–early winter. |
Habitat | Waste areas, disturbed sites, roadsides, fields, pastures. | Desert scrub, desert grasslands, mesquite woodlands. |
Elevation | 30–900 m. (100–3000 ft.) | 200–1200 m. (700–3900 ft.) |
Distribution |
CA; OR; WA; s Europe [Introduced in North America]
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AZ; Mexico (Baja California Sur, Sonora) |
Discussion | Euphorbia oblongata is listed as a noxious weed by the states of California, Oregon, and Washington. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia trachysperma may be expected in extreme southwestern New Mexico given the close proximity of some collections in southeastern Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 305. | FNA vol. 12, p. 291. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus oblongatus | Chamaesyce trachysperma |
Name authority | Grisebach: Spic. Fl. Rumel. 1: 136. (1843) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) |
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