Euphorbia discoidalis |
Euphorbia porteriana |
|
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summer spurge |
Porter's sandmat |
|
Habit | Herbs, perennial, with spreading rootstock. | Herbs, usually annual, sometimes perennial, with slender to occasionally thickened taproot, 5 mm diam.. |
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, sometimes slightly woody at base, not mat-forming, 15–60 cm, usually glabrous, young branches rarely very sparsely short pubescent. |
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 usually distinct, occasionally connate basally, triangular, entire or 2–4 parted, apically ciliate, 0.3–0.4 mm, usually glabrous, rarely very sparsely short pubescent; petiole 0.5–1.5 mm, usually glabrous, rarely very sparsely short pubescent; blade ovate, oval, elliptic, oblong-elliptic, or linear-elliptic, 4–12 × 1–7 mm, base asymmetric, rounded or subcordate, margins usually entire, rarely sparsely serrate, apex obtuse to acute, sometimes mucronate, surfaces abaxially often purple or red, adaxially green, usually glabrous, rarely very sparsely short pubescent; 3-veined from base, 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. |
turbinate to campanulate, 0.7–1 × 0.8–1 mm, usually glabrous, rarely very sparsely short pubescent; glands 4, brown, slightly concave, elliptic-oblong, 0.1–0.2 × 0.3–0.6 mm; appendages white or pink to dark red, usually oblong or flabellate, occasionally rudimentary and forming narrow rim at edge of gland, (0–)0.1–0.2 × 0.4–1 mm, distal margin entire or crenulate. |
Staminate flowers | 20–25. |
8–14. |
Pistillate flowers | ovary glabrous or sparsely strigose; styles 0.5–1.1 mm, 2-fid at apex to 1/2 length. |
ovary glabrous, subtended by triangular calyxlike structure; styles 0.4–0.6 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. |
broadly ovoid, 1–1.5 × 1.7–2.1 mm, glabrous; columella 1–1.4 mm. |
Seeds | light gray, ovoid, 2 × 1.2–1.3 mm, smooth or with few, very shallow depressions; caruncle absent. |
reddish brown, ovoid, 4-angled in cross section, 0.7–1 × 0.6–0.7 mm, smooth or obscurely wrinkled. |
Cyathia | in terminal pleiochasia; peduncle 5–15 mm, filiform, glabrous or very sparsely puberulent to sericeous. |
solitary at distal nodes; peduncle 0.5–1.1 mm. |
Euphorbia discoidalis |
Euphorbia porteriana |
|
Phenology | Flowering and fruiting late spring–fall. | Flowering and fruiting year-round. |
Habitat | Sand hills, pine savannas, woodland borders, open fields with sandy soils. | Pine rocklands, coastal scrub, open hammocks. |
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 porteriana is found in Miami-Dade County and on Big Pine Key, Monroe County. This species is closely related to E. blodgettii, E. garberi, and E. serpens. The capsules of E. porteriana are almost always completely glabrous, but the authors have seen three specimens with just a few scattered hairs on the keels. A. Herndon (1993) synonymized E. porteriana var. keyensis under E. garberi because of its uniformly hairy capsules, and that treatment is followed here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 245. | FNA vol. 12, p. 285. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalopsis discoidalis | Chamaesyce porteriana, C. porteriana var. scoparia, C. scoparia |
Name authority | Chapman: Fl. South. U.S., 401. (1860) | (Small) Oudejans: Phytologia 67: 48. (1989) |
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