Euphorbia graminea |
Euphorbia longicruris |
|
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grassleaf spurge |
wedge-leaf spurge |
|
Habit | Herbs, usually annual, rarely perennial, with slender, rarely tuberous, taproot. | Herbs, annual, with taproot. |
Stems | erect or ascending, branched, 30–80(–110) cm, strigillose or glabrescent, sharply angled. |
erect, usually unbranched, occasionally branched later in season, 5–25 cm, glabrous. |
Leaves | usually alternate, sometimes some opposite; stipules usually 0.2–0.5 mm, rarely rudimentary; petiole 0.4–5.9 mm, strigillose; blade ovate, elliptic, linear-elliptic, or oblong, 10–83 × 3–39 mm, base attenuate, rounded, or cuneate, margins entire, apex acute or obtuse, surfaces strigillose; venation occasionally obscure on narrow leaves, midvein conspicuous. |
petiole 0–0.5 mm; blade cuneate-spatulate to obovate, 5–15 × 2–6 mm, base broadly attenuate, margins entire, apex rounded to obtuse, mucronate, surfaces glabrous; venation pinnate, midvein prominent. |
Involucre | campanulate or obconic, 1–1.8 × 0.8–1.7 mm, glabrous or strigillose toward rim; glands (1–)2–4, yellow to greenish, elliptic or oblong, 0.1–0.3 × 0.2–0.4 mm; appendages white to tinged purple, ovate and often hoodlike or forming narrow rim around distal margin of gland, 0.3–1.6 × 0.4–0.9 mm, entire. |
campanulate, 1.5–2 × 1–1.5 mm, glabrous; glands 4, crescent-shaped to elliptic, 0.4–0.8 × 0.8–1.1 mm; horns divergent, 0.5–0.8 mm. |
Staminate flowers | 30–40. |
10–15. |
Pistillate flowers | ovary glabrous; styles 0.7–1 mm, 2-fid from 1/2 to nearly entire length. |
ovary glabrous; styles 0.5–0.6 mm, 2-fid. |
Capsules | ovoid-oblate, 2.5–3 × 3–3.5 mm, glabrous; columella 1.6–1.9 mm. |
ovoid-globose, 2–2.8 × 2.5–3 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 1.6–2.1 mm. |
Seeds | gray, brown, or nearly black, ovoid, circular or weakly angled in cross section, 1.5–1.7 × 1.3–1.5 mm, coarsely tuberculate with longitudinal rows of shallow pits; caruncle absent or punctiform, 0.1–0.2 mm. |
gray to purple-gray or sometimes nearly black, oblong, 1.3–1.6 × 0.9–1.2 mm, strongly small-pitted; caruncle umbonate, depressed-conic, 0.5 × 0.7 mm. |
Cyathia | in usually terminal, rarely axillary, dichasia, distal dichasial bracts often white; peduncle 0.4–4.5 mm (to 15 mm at first node of inflorescence), glabrous. |
peduncle 0.3–0.5 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3, each many times 2-branched; pleiochasial bracts obovate, similar in size to distal leaves; dichasial bracts basally subconnate, strongly imbricate and often obscuring internodes, reniform to semiorbiculate, base cordate, margins entire, apex rounded; axillary cymose branches 0–5. |
|
Euphorbia graminea |
Euphorbia longicruris |
|
Phenology | Flowering and fruiting year-round. | Flowering and fruiting spring. |
Habitat | Disturbed, weedy, or urban areas. | Grasslands, open prairies, sites with rocky, usually calcareous soils. |
Elevation | 0–500 m. (0–1600 ft.) | 300–800 m. (1000–2600 ft.) |
Distribution |
AR; CA; FL; LA; TX; Mexico; Central America; South America [Introduced in North America; introduced also in West Indies, Asia, Pacific Islands]
|
AR; KS; OK; TX |
Discussion | Euphorbia graminea occurs natively from northern South America to northern Mexico. The species is a variable and taxonomically complex entity whose boundaries are not well defined and are in need of further study. Euphorbia graminea is often weedy and has recently become established in warmer areas of the southern United States, where it will likely become more common in the future. In recent years, a cultivar of E. graminea has found considerable horticultural success and is marketed under the trade name "Diamond Frost." (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia longicruris is quite similar to the other small, annual members of subg. Esula in the south-central United States and can best be distinguished from those species by its imbricate dichasial bracts that form little tufts of overlapping leaves at the ends of the pleiochasial branches. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 246. | FNA vol. 12, p. 304. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Tithymalus longicruris | |
Name authority | Jacquin: Select. Stirp. Amer. Hist., 151. (1763) | Scheele: Linnaea 22: 152. (1849) |
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