Euphorbia discoidalis |
Euphorbia mesembrianthemifolia |
|
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summer spurge |
coastal beach sandmat |
|
Habit | Herbs, perennial, with spreading rootstock. | Subshrubs or shrubs, perennial, with thickened and often woody 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. |
erect to ascending, or nearly decumbent in shifting sand, 25–60 cm, glabrous. |
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. |
opposite; stipules connate, forming conspicuous, ligulate or deltate scale, short cleft or fringed, 1–1.8 mm, glabrous; petiole 0.5–1 mm, glabrous; blade ovate to elliptic often folded along midrib, 5–12 × 3–8 mm, ± fleshy, base slightly asymmetric, truncate to cordate, partially obscuring stem, margins entire, apex usually obtuse, rarely acute, surfaces yellowish to dark green, glabrous glaucous; obscurely 3–5-veined at base, pinnate distally, 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, 1–1.6 × 0.7–1.2 mm, glabrous; glands 4, brown, usually elliptic, occasionally almost round, 0.2–0.4 × 0.5–0.7 mm, fleshy; appendages white, oblong, rarely rudimentary, 0.2–0.4 × 0.5–0.9 mm, distal margin entire or undulate. |
Staminate flowers | 20–25. |
12–20. |
Pistillate flowers | ovary glabrous or sparsely strigose; styles 0.5–1.1 mm, 2-fid at apex to 1/2 length. |
ovary glabrous; styles 0.3–0.4 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. |
subglobose subtended by calyxlike structure, 1.5–2 × 2.2–2.8 mm, glabrous; columella 1–1.5 mm. |
Seeds | light gray, ovoid, 2 × 1.2–1.3 mm, smooth or with few, very shallow depressions; caruncle absent. |
ashen, broadly ovoid, angled in cross section, faces plump, convex, 1.2–1.3 × 0.9–1.2 mm, obscurely pitted. |
Cyathia | in terminal pleiochasia; peduncle 5–15 mm, filiform, glabrous or very sparsely puberulent to sericeous. |
solitary at distal nodes; peduncle 0.5–1 mm. |
Euphorbia discoidalis |
Euphorbia mesembrianthemifolia |
|
Phenology | Flowering and fruiting late spring–fall. | Flowering and fruiting year-round. |
Habitat | Sand hills, pine savannas, woodland borders, open fields with sandy soils. | Sandy and rocky shores, associated beach scrub. |
Elevation | 0–150 m. (0–500 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AL; FL; GA; LA; MS; TX
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FL; Mexico; West Indies; Bermuda; South America (Colombia, Venezuela) |
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 mesembrianthemifolia is found in the flora area along the sandy and rocky shores of southern Florida from Pinellas and Volusia counties southward. It is one of the few members of subg. Chamaesyce in the flora area that is a shrub or subshrub. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 245. | FNA vol. 12, p. 277. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalopsis discoidalis | Chamaesyce buxifolia, C. mesembrianthemifolia, E. buxifolia |
Name authority | Chapman: Fl. South. U.S., 401. (1860) | Jacquin: Enum. Syst. Pl., 22. (1760) |
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