Euphorbia curtisii |
Euphorbia platysperma |
|
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Curtis' spurge, Sandhills spurge |
dune spurge, flat-seed spurge, flatseed sandmat |
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Habit | Herbs, perennial, with spreading rootstock. | Herbs, annual or short-lived perennial, with slender 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. |
prostrate, spreading and often mat-forming, 10–100 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. |
opposite; stipules usually distinct, occasionally connate basally, rarely to middle, subulate, narrowly triangular, or divided into 2–4 subulate segments, 0.5–1.1 mm, glabrous; petiole 1–3.6 mm, glabrous; blade oblong to obovate, 5–12 × 3–5 mm, base subsymmetric, cuneate to attenuate, margins entire, apex usually acute to mucronulate, rarely obtuse, surfaces glabrous; only midvein conspicuous. |
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 to obconic, 1.5–2 × 1.3–2.5 mm, glabrous; glands 4, yellowish, subcircular to oblong, 0.5–0.6 × 0.5–0.6 mm; appendages white, ovate to oblong or almost triangular, 0.3–0.6 × 0.3–0.8 mm, distal margin entire or shallowly 2–3-lobed. |
Staminate flowers | 20–25. |
45–50. |
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 0.4–0.6 mm, 2-fid 1/2 length. |
Capsules | globose, 2.5–3.2 × 4.3–5.1 mm, glabrous or sparsely strigose to sericeous; columella 2.4–3.1 mm. |
ovoid to ellipsoid, 2.7–3.2 × 2.2–2.9 mm, glabrous; columella 2.6–2.8 mm. |
Seeds | usually gray to black, occasionally brown, ovoid-globose, 2.2 × 1.8 mm, smooth; caruncle absent. |
whitish, pinkish, or light brown, ellipsoid-oblong, weakly dorsiventrally compressed and semielliptic in cross section, 2.2–2.5 × 1.3–1.6 mm, with sharp linelike longitudinal ridge on adaxial side, smooth and rounded on back. |
Cyathia | in terminal pleiochasia (fertile axillary branches occasionally present); peduncle 6.5–17 mm, filiform, glabrous. |
solitary at distal nodes; peduncle 1.6–4.1 mm. |
Euphorbia curtisii |
Euphorbia platysperma |
|
Phenology | Flowering and fruiting early spring–summer. | Flowering and fruiting year-round in response to sufficient moisture. |
Habitat | Xeric to dry oak or oak-pine scrub of sand hills, pine-oak woodlands, pine-oak savannas. | Sand dunes in Sonoran Desert scrub. |
Elevation | 0–200 m. (0–700 ft.) | 60–200 m. (200–700 ft.) |
Distribution |
FL; GA; NC; SC
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AZ; CA; Mexico (Baja California, Sonora) |
Discussion | Euphorbia curtisii is found in the Gulf and Atlantic coastal plains. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 245. | FNA vol. 12, p. 282. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | E. eriogonoides, Tithymalopsis curtisii, T. eriogonoides | Chamaesyce platysperma |
Name authority | Engelmann ex Chapman: Fl. South. U.S., 401. (1860) | Engelmann: in W. H. Brewer et al., Bot. California 2: 482. (1880) |
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