Euphorbia discoidalis |
Euphorbia meganaesos |
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summer spurge |
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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 to ascending, drooping at tips, 15–30 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 distinct, divided nearly to base into linear-filiform segments, 1–2 mm, glabrous; petiole 0.5–1.3 mm, glabrous; blade narrowly oblong to oblong-obovate, often ± falcate, 5–16 × 1–4.5 mm, base subsymmetric to strongly oblique, margins sparsely spinulose-serrulate, apex rounded or broadly acute, abaxial surface pale grayish green, adaxial surface sometimes with reddish streak along midvein, both surfaces not papillate, glabrous; 3–5-veined at base. |
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. |
obconic, 0.7–0.9 × 0.4–0.6 mm, glabrous; glands 4, green to yellow-green, subequal, oblong, 0.1–0.2 × 0.2–0.3 mm; appendages white to reddish tinged, lunate to oblong, 0.1–0.3 × 0.3–0.5 mm (2 ± 2 times longer than other 2), entire or coarsely toothed. |
Staminate flowers | 20–25. |
2–5. |
Pistillate flowers | ovary glabrous or sparsely strigose; styles 0.5–1.1 mm, 2-fid at apex to 1/2 length. |
ovary glabrous; styles 0.2–0.3 mm, 2-fid at apex to nearly 1/2 length. |
Capsules | globose, 1.8–3 × 2.5–4.8 mm, glabrous or sparsely strigose; columella 2.3–2.5 mm. |
ovoid, cocci not elongated nor terminating in empty portion, 1.5 × 1.7 mm, glabrous; columella 1.3 mm. |
Seeds | light gray, ovoid, 2 × 1.2–1.3 mm, smooth or with few, very shallow depressions; caruncle absent. |
reddish brown to brown, pyramidal to oblong-ovoid, weakly 4-angled in cross section, 0.9–1 × 0.7 mm, minutely beaded, with 3–4 broad, rounded, transverse ridges that do not interrupt abaxial keel. |
Cyathia | in terminal pleiochasia; peduncle 5–15 mm, filiform, glabrous or very sparsely puberulent to sericeous. |
solitary at distal nodes or on congested, axillary branches; peduncle 0.1–0.4 mm. |
Euphorbia discoidalis |
Euphorbia meganaesos |
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Phenology | Flowering and fruiting late spring–fall. | Flowering and fruiting late spring–late summer. |
Habitat | Sand hills, pine savannas, woodland borders, open fields with sandy soils. | Sandy beaches, edges of marshes, coastal prairies, roadsides. |
Elevation | 0–150 m. (0–500 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AL; FL; GA; LA; MS; TX
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LA; 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 meganaesos is known only from coastal areas of southern Louisiana and adjacent Texas. This species was often considered conspecific with E. maculata in the past, but it differs from that species in being entirely glabrous. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 245. | FNA vol. 12, p. 276. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalopsis discoidalis | |
Name authority | Chapman: Fl. South. U.S., 401. (1860) | Featherman: Rep. (Annual) Board Supervisors Louisiana State Seminary Learning Military Acad. 1870: 71, 105. (1871) |
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