Euphorbia curtisii |
Euphorbia helleri |
|
---|---|---|
Curtis' spurge, Sandhills spurge |
Heller's spurge |
|
Habit | Herbs, perennial, with spreading rootstock. | Herbs, annual, with taproot. |
Stems | erect or ascending, branched, solitary or few, previous year's dead stems not persistent, 20–40 cm, usually glabrous, rarely strigose to sericeous at nodes. |
ascending, branched proximally, 15–30 cm, glabrous. |
Leaves | alternate; stipules to 0.1 mm; petiole to (0–)1–2 mm, glabrous or strigose to sericeous; blade usually linear, occasionally elliptic, rarely ovate, proximal often greatly reduced and often scalelike, 10–30 × 1.5–6 mm, base cuneate, margins entire, occasionally sparsely ciliate, apex rounded or broadly acute, abaxial surface glabrous or sparsely strigose to sericeous, adaxial surface glabrous; venation obscure, only midvein conspicuous. |
petiole usually 1–3 mm, absent distally; blade spatulate, 6–15 × 3–5 mm, base broadly attenuate, margins entire, apex usually obtuse to rounded, sometimes retuse, surfaces glabrous; venation pinnate, midvein prominent. |
Involucre | campanulate, 1–1.2 × 1.3–1.5(–1.7) mm, glabrous or strigose to sericeous on distal 1/2; glands 5, green, reniform, 0.3 × 0.6 mm; appendages white, semicircular, 0.3–0.4 × 0.6–0.8 mm, entire. |
campanulate, 0.9–1.2 × 0.7–1 mm, glabrous; glands 4, elliptic, 0.1–0.2 × 0.3–0.4 mm; horns slightly divergent, 0.1–0.2 mm. |
Staminate flowers | 20–25. |
8–10. |
Pistillate flowers | ovary glabrous or sparsely strigose to sericeous; styles 0.6–1.1 mm, 2-fid at apex to 1/2 length. |
ovary glabrous; styles 0.4–0.5 mm, 2-fid. |
Capsules | globose, 2.5–3.2 × 4.3–5.1 mm, glabrous or sparsely strigose to sericeous; columella 2.4–3.1 mm. |
depressed-globose, 2.1–2.5 × 2.5–3 mm, 3-lobed; cocci flattened, smooth, glabrous; columella 1.2–1.7 mm. |
Seeds | usually gray to black, occasionally brown, ovoid-globose, 2.2 × 1.8 mm, smooth; caruncle absent. |
white to light gray, ovoid, 1.4–1.6 × 1–1.2 mm, smooth; caruncle 2-lobed, thin, 0.4 × 0.7 mm. |
Cyathia | in terminal pleiochasia (fertile axillary branches occasionally present); peduncle 6.5–17 mm, filiform, glabrous. |
peduncle 0.2–0.4 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3, each 1–5 times 2-branched; pleiochasial bracts oblong, similar in size to distal leaves; dichasial bracts distinct, orbiculate-ovate to nearly reniform, subpandurate, base broadly cuneate to truncate, margins entire, apex obtuse, mucronate; axillary cymose branches 0–5. |
|
Euphorbia curtisii |
Euphorbia helleri |
|
Phenology | Flowering and fruiting early spring–summer. | Flowering and fruiting late winter–spring. |
Habitat | Xeric to dry oak or oak-pine scrub of sand hills, pine-oak woodlands, pine-oak savannas. | Forests, stream banks, roadsides, shaded areas with sandy, calcareous soils. |
Elevation | 0–200 m. (0–700 ft.) | 0–50 m. (0–200 ft.) |
Distribution |
FL; GA; NC; SC
|
LA; TX; Mexico (Nuevo León) |
Discussion | Euphorbia curtisii is found in the Gulf and Atlantic coastal plains. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The smooth, white to light gray seeds of Euphorbia helleri easily distinguish it from other annual members of subg. Esula in North America. Collections of E. helleri have been made near Brownsville, Texas, and thus it is possible that the species occurs in northern Tamaulipas, Mexico. The Louisiana record (Webster Parish) likely represents introduced plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 245. | FNA vol. 12, p. 303. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | E. eriogonoides, Tithymalopsis curtisii, T. eriogonoides | Tithymalus helleri |
Name authority | Engelmann ex Chapman: Fl. South. U.S., 401. (1860) | Millspaugh: Bot. Gaz. 26: 268, fig. [p. 270]. (1898) |
Web links |