Euphorbia discoidalis |
Euphorbia conferta |
|
---|---|---|
summer spurge |
Everglade key sandmat |
|
Habit | Herbs, perennial, with spreading rootstock. | Herbs, annual, with taproot. |
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, ascending, to erect, 10–45 cm, 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. |
opposite; stipules distinct, subulate, 1–2 mm, pilose; petiole 0.9–1.5 mm, pilose; blade oblanceolate to elliptic, 3–10 × 1–4 mm, base asymmetric, obtuse to hemicordate, margins coarsely serrate, sometimes revolute, apex rounded to acute, abaxial surface sparsely hispidulous to strigillose (densely so on young leaves), adaxial surface glabrous; 3-veined from base but 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, 1.1–1.4 × 0.5–0.7 mm, pilose; glands 4, red, narrowly reniform, 0.1 × 0.2–0.4 mm; appendages pink to red, larger 2 petal-like, smaller 2 elliptic, 0.4–1 × 0.3–0.5 mm, distal margin erose. |
Staminate flowers | 20–25. |
5–8. |
Pistillate flowers | ovary glabrous or sparsely strigose; styles 0.5–1.1 mm, 2-fid at apex to 1/2 length. |
ovary pilose; styles 0.4–0.8 mm, 2-fid at apex. |
Capsules | globose, 1.8–3 × 2.5–4.8 mm, glabrous or sparsely strigose; columella 2.3–2.5 mm. |
conic or truncate-ovoid, 1–1.2 mm diam., pilose; columella 0.9–1.1 mm. |
Seeds | light gray, ovoid, 2 × 1.2–1.3 mm, smooth or with few, very shallow depressions; caruncle absent. |
orange-brown, glaucous, oblong, 4-angled in cross section, 0.7–0.8 × 0.4–0.5 mm, slightly rugose and with 3–4 transverse ridges. |
Cyathia | in terminal pleiochasia; peduncle 5–15 mm, filiform, glabrous or very sparsely puberulent to sericeous. |
solitary at distal nodes (appearing clustered at points of new growth); peduncle 0.4–0.6 mm. |
Euphorbia discoidalis |
Euphorbia conferta |
|
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, disturbed, wet areas, often roadsides. |
Elevation | 0–150 m. (0–500 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AL; FL; GA; LA; MS; TX
|
FL |
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 conferta is known only from Broward, Miami-Dade, and Monroe counties in southern Florida. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 245. | FNA vol. 12, p. 264. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalopsis discoidalis | Chamaesyce conferta |
Name authority | Chapman: Fl. South. U.S., 401. (1860) | (Small) B. E. Smith: J. Elisha Mitchell Sci. Soc. 62: 82. (1946) |
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