Euphorbia bilobata |
Euphorbia terracina |
|
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black-seed spurge |
carnation spurge, Geraldton carnation weed, terracina spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, perennial or biennial, with taproot. |
Stems | erect, branched, 10–35 cm, glabrous or strigillose (especially when young and around nodes). |
erect, unbranched or branched, 10–100 cm, glabrous. |
Leaves | opposite proximally, alternate distally; stipules 0.1–0.2 mm; petiole 1–4(–6) mm, glabrous, sericeous or strigillose; blade linear to narrowly elliptic, 8–52 × 2–7 mm, base attenuate, margins entire, ciliate-strigose, apex acute, abaxial surface sparsely strigillose to sericeous, adaxial surface usually glabrous; venation obscure, only midvein conspicuous. |
petiole absent; blade linear, linear-lanceolate, oblong-elliptic, or obovate, 4–50 × 2–10 mm, base obtuse or truncate, margins finely serrulate, apex acute, obtuse, or truncate, sometimes mucronulate, surfaces glabrous; venation inconspicuous, only midvein prominent. |
Involucre | obconic, 0.9–1.5 × 0.9–1.3 mm, strigillose to pilose; glands 5, yellow or pink, U-shaped, 0.2–0.3 × 0.4–0.5 mm; appendages greenish, white, or pink, forming narrow rim around gland, or ovate, oblong, or obovate and usually 2-fid, rarely rudimentary, 0.2–1.4 × 0.2–0.6 mm, entire. |
cupulate to slightly turbinate, 1.1–2 × 1.3–1.5 mm, glabrous or puberulent; glands 4, elliptic to trapezoidal, 0.6–0.8 × 1–2 mm; horns slightly convergent to divergent, 1–2 mm. |
Staminate flowers | 20–25. |
15–20. |
Pistillate flowers | ovary glabrous, puberulent, strigillose, or pilose; styles 0.5–0.8 mm, 2-fid 1/3–1/2 length. |
ovary glabrous; styles 1–1.8 mm, 2-fid. |
Capsules | oblate, 1.5–2.6 × 2.1–3.3 mm, glabrous or puberulent, strigillose, or pilose; columella 1.2–2.1 mm. |
depressed-globose, 2.5–3 × 3–4.5 mm, deeply 3-lobed; cocci rounded to subangular, smooth, glabrous; columella 1.9–2.3 mm. |
Seeds | brown to grayish black, narrowly ovoid, 3- or 4-angled in cross section, sometimes obscurely so, 1.3–1.9 × 1–1.4 mm, tuberculate, often with shallow depressions; caruncle absent. |
pale gray, subovoid, 1.6–2.4 × 1.3–1.8 mm, smooth; caruncle boat-shaped, 0.4–0.6 × 0.4–0.6 mm. |
Cyathia | solitary at distal nodes or in weakly defined cymes or dichasia, dichasial bracts and distal stem leaves wholly green; peduncle 0.5–3.6 mm, strigillose. |
peduncle 1–3 mm. |
Cyathial | arrangement: terminal pleiochasial branches 2–5, each 1–5 times 2-branched; pleiochasial bracts lanceolate, elliptic or ovate, similar in size to distal leaves; dichasial bracts distinct, ovate to subreniform, base cuneate to cordate, margins finely serrulate, apex acute, obtuse, or rounded, sometimes mucronulate or cuspidate; axillary cymose branches 0–7. |
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2n | = 32. |
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Euphorbia bilobata |
Euphorbia terracina |
|
Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting spring–summer. |
Habitat | Sandy and rocky soils on slopes and canyon bottoms in pine-juniper woodlands, oak woodlands, grasslands. | Edges of cultivated fields and woodlands, roadsides, waste areas, pastures, coastal bluffs, dunes, riparian areas. |
Elevation | 1400–2600 m. (4600–8500 ft.) | 0–300 m. (0–1000 ft.) |
Distribution |
AZ; NM; TX; Mexico (Chihuahua, Durango, Sonora)
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CA; Europe [Introduced in North America; introduced also in Mexico, s Africa, Australia]
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Discussion | In Texas, Euphorbia bilobata is known only from Jeff Davis County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia terracina is native to the Mediterranean region of Europe. This species is invasive and spreading rapidly, displacing native coastal scrub in southern California, and has been listed as a noxious weed by that state. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 243. | FNA vol. 12, p. 310. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Tithymalus terracinus | |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 190. (1859) | Linnaeus: Sp. Pl. ed. 2, 1: 654. (1762) |
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