Euphorbia agraria |
Euphorbia perennans |
|
---|---|---|
urban spurge |
perennial sandmat, Terlingua spurge |
|
Habit | Herbs, perennial, with slender, spreading rootstock. | Herbs, perennial, with strongly thickened, woody rootstock. |
Stems | erect or ascending, unbranched or branched, 30–90 cm, glabrous. |
erect, 7–45 cm, glabrous. |
Leaves | petiole absent; blade oblong-elliptic, 20–65 × 9–20 mm, base truncate to auriculate, margins entire, apex obtuse to rounded, surfaces glabrous; venation conspicuously pinnate, midvein prominent. |
opposite; stipules distinct, linear-filiform in (1–)2(–3) segments, 0.3–0.4 mm, glabrous; petiole 0.8–2 mm, glabrous; blade ovate or orbiculate-deltate to reniform-deltate, 5–17 × 4–16 mm midstem leaves largest, base symmetric, cuneate, rounded to cordate, margins entire, apex acute to rounded, surfaces glabrous, often glaucous; 3-veined from base, only midvein conspicuous. |
Involucre | campanulate, 2.2–3 × 1.8–2 mm, glabrous; glands 4, crescent-shaped; 0.6–1 × 1–2 mm; horns slightly divergent to convergent, 0.1–0.2 mm. |
broadly-campanulate to hemispheric, 1.7–2.2 × 1.5–2.7 mm, glabrous; glands 4, green to yellow-green, elliptic to oblong, folded longitudinally, 0.3–0.5 × 0.7–1.4 mm; appendages absent. |
Staminate flowers | 15–20. |
35–45. |
Pistillate flowers | ovary glabrous; styles 1.2–2 mm, 2-fid. |
ovary glabrous; styles 0.7–0.9 mm, 2-fid nearly entire length. |
Capsules | globose, 2–2.8 × 2.2–2.7 mm, 3-lobed; cocci rounded, smooth except finely granulate toward abaxial line, glabrous; columella 2.1–2.7 mm. |
subglobose to broadly ovoid, 2.8–3.3 × 2.8–3.4 mm, glabrous; columella 2.2–2.7 mm. |
Seeds | gray or whitish, ovoid-oblong, 2–2.1 × 1.2–1.3 mm, smooth; caruncle ± rounded and flattened, 0.8 × 0.6 mm. |
white to light brown, ovoid, 3–4-angled in cross section, 2–2.4 × 1–1.2 mm, smooth to faintly transverse-wrinkled. |
Cyathial | arrangement: terminal pleiochasial branches 8–15, 1–2 times 2-branched; pleiochasial bracts similar in shape but shorter and narrower than distal leaves; dichasial bracts distinct, rhombic to reniform, base obtuse, margins entire, apex obtuse, mucronate; axillary cymose branches 12–23. |
|
Cyathia | peduncle 0–2 mm. |
solitary at distal nodes or at nodes of short, axillary branches; peduncle 1.8–3 mm. |
Euphorbia agraria |
Euphorbia perennans |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring–fall. |
Habitat | Grasslands, roadside banks, pastures. | Desert scrub, on cretaceous and gypseous clay, limestone hills and flats. |
Elevation | 200–1600 m. (700–5200 ft.) | 900–1200 m. (3000–3900 ft.) |
Distribution |
KS; MT; NE; NY; PA; WA; WY; AB; SK; Europe [Introduced in North America]
|
TX; Mexico (Chihuahua) |
Discussion | Euphorbia perennans is a distinctive species with an erect habit and relatively large, firm, deltate midstem leaves. Phylogenetic data place E. perennans in a clade of primarily Chihuahuan Desert annual and perennial species (for example, E. chaetocalyx, E. fendleri, E. golondrina, E. simulans, E. spurca, and E. theriaca; Y. Yang and P. E. Berry 2011). Euphorbia perennans is known in the flora area only from Brewster County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 282. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus agrarius | Chamaesyce perennans |
Name authority | M. Bieberstein: Fl. Taur.-Caucas. 1: 375. (1808) | (Shinners) Warnock & M. C. Johnston: SouthW. Naturalist 5: 170. (1960) |
Web links |