Euphorbia discoidalis |
Euphorbia innocua |
|
---|---|---|
summer spurge |
velvet spurge |
|
Habit | Herbs, perennial, with spreading rootstock. | Herbs, perennial, with moderately to strongly thickened rootstock. |
Stems | erect or ascending, unbranched, solitary or few, previous year's dead stems not persistent, 45–70 cm, usually densely puberulent to sericeous, rarely glabrous. |
prostrate to decumbent or ascending, branched (often near base), 7–45 cm, densely pilose. |
Leaves | alternate; stipules to 0.1 mm; petiole (0–)1–2 mm (or absent), densely puberulent; blade usually linear, rarely ovate, 25–55 × 1.5–4 mm, base cuneate, margins entire, revolute, apex rounded, abaxial surface glabrous or puberulent to sericeous, adaxial surface glabrous; venation often obscure on smaller leaves, midvein conspicuous. |
alternate; stipules to 0.1 mm; petiole (0.7–)1.1–3.5 mm, pilose; blade ovate to orbiculate, 4.6–17(–25) × 4.5–15(–19) mm, base cordate, margins entire, apex rounded to obtuse, surfaces densely pilose; venation obscure, usually only midvein conspicuous. |
Involucre | campanulate, 1.2–1.4 × 1.2–2 mm, sparsely to densely puberulent; glands 5, green, reniform, 0.2–0.3 × 0.5–0.6 mm; appendages white, orbiculate to oblong, (0.5–)1–1.7 × 1–1.5 mm, entire. |
campanulate, 1–1.3 × 1.2–1.4 mm, pilose; glands 4, yellow to green, elliptic, 0.2–0.3 × 0.5–0.6 mm; appendages green, elliptic, 0.4–0.5 × 0.5–0.9 mm, entire or crenulate, ciliate. |
Staminate flowers | 20–25. |
5–10. |
Pistillate flowers | ovary glabrous or sparsely strigose; styles 0.5–1.1 mm, 2-fid at apex to 1/2 length. |
ovary pilose; styles 0.4–0.7 mm, 2-fid 1/2 length. |
Capsules | globose, 1.8–3 × 2.5–4.8 mm, glabrous or sparsely strigose; columella 2.3–2.5 mm. |
depressed-ovoid, 2–2.5 × 2.7–3.3 mm, pilose; columella 1.6–2.1 mm. |
Seeds | light gray, ovoid, 2 × 1.2–1.3 mm, smooth or with few, very shallow depressions; caruncle absent. |
gray to brown, ovoid, 1.5–1.7 × 1.2–1.3 mm, rugose with whitish ridges; caruncle absent. |
Cyathia | in terminal pleiochasia; peduncle 5–15 mm, filiform, glabrous or very sparsely puberulent to sericeous. |
in terminal dichasia (often weakly defined); peduncle 1–2.7 mm, densely pilose. |
Euphorbia discoidalis |
Euphorbia innocua |
|
Phenology | Flowering and fruiting late spring–fall. | Flowering and fruiting early winter–late spring. |
Habitat | Sand hills, pine savannas, woodland borders, open fields with sandy soils. | Sandy soils or dunes, grasslands, pastures. |
Elevation | 0–150 m. (0–500 ft.) | 0–20 m. (0–100 ft.) |
Distribution |
AL; FL; GA; LA; MS; TX
|
TX |
Discussion | M. J. Huft (1979) remarked that Euphorbia discoidalis is uncommon west of Alabama and referred many narrow-leaved specimens from Louisiana and Texas to E. corollata. K. R. Park (1998) included them in an expanded E. discoidalis, and that is followed here. The western populations can be distinguished from E. corollata by their shorter involucral gland appendages and revolute leaf margins. Further study of these western populations is warranted. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia innocua is restricted to south coastal Texas in Aransas, Calhoun, Kenedy, Kleberg, Nueces, Refugio, San Patricio, and Willacy counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 245. | FNA vol. 12, p. 247. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Tithymalopsis discoidalis | |
Name authority | Chapman: Fl. South. U.S., 401. (1860) | L. C. Wheeler: Contr. Gray Herb. 127: 62, plate 3, fig. D. (1939) |
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