Euphorbia radians |
Euphorbia cumulicola |
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sun spurge |
coastal dune sandmat |
|
Habit | Herbs, perennial, with moniliform tuberous rootstock. | Herbs, usually annual, rarely perennial, with taproot. |
Stems | erect, 5–20(–30) cm, usually glabrous, occasionally puberulent; branches ± straight. |
prostrate, 10–20 cm, glabrous. |
Leaves | alternate; petiole 0–2 mm, glabrous or strigose; blade linear-lanceolate to ovate or broadly elliptic, 25–50 × 3–20 mm, unlobed, base rounded (tapered to petiole), margins with few glandular teeth, strigillose, flat to revolute, apex acute, abaxial surface coarsely strigose, adaxial surface strigose-hirsute; venation pinnate, midvein prominent. |
opposite; stipules distinct, linear-subulate, usually divided into 3–7 linear segments, 0.5–1 mm, glabrous; petiole 0.5–1 mm, glabrous; blade narrowly elliptic to lanceolate, 4–8 × 1–2 mm uniform in size, base asymmetric, obtuse to rounded, margins entire, apex obtuse to acute, surfaces green to reddish flushed, glabrous; only midvein conspicuous. |
Involucre | broadly globose-cupulate, 1.7–2.1 × 2.2–2.5 mm, glabrous or puberulent; involucral lobes divided into triangular segments; glands 1–4(–5), white, sessile and broadly attached, 1.1 × 1.4 mm, opening oblong, glabrous; appendages absent. |
campanulate, 0.9–1.1 × 1–1.3 mm, glabrous; glands 4, green to red, slightly stipitate, subcircular, 0.1 × 0.1 mm; appendages white or pink, fringing edge of gland, short-flabellate, often rudimentary, 0.1–0.2 × 0.1 mm, distal margin crenate or entire. |
Staminate flowers | 20–25. |
5–8. |
Pistillate flowers | ovary glabrous or puberulent, styles 3–4 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous; styles 0.2–0.3 mm, 2-fid at apex to nearly 1/2 length. |
Capsules | depressed-globose, 3.8–5 × 4–5 mm, 3-lobed, glabrous or puberulent; columella 3.6–4.5 mm. |
ovoid or subglobose, 1.8–2 × 2–2.3 mm, glabrous; columella 1.2–1.5 mm. |
Seeds | white, mottled brown to gray, ellipsoid, rounded in cross section, 4–4.6 × 2.4–3.2 mm, smoothly and broadly pitted or grooved; caruncle 0.1 mm. |
white to gray-brown, ovoid, terete to bluntly subangled in cross section, 1–1.3 × 1 mm, smooth or minutely pitted, with smooth brown line from top to bottom on adaxial side. |
Cyathial | arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched (often highly condensed); pleiochasial bracts 6–8(–10), as tight involucrate whorl, wholly white to pale pink or red, usually narrower than distal leaves; dichasial bracts linear and highly reduced. |
|
Cyathia | peduncle 2–5.5 mm. |
solitary at distal nodes; peduncle 1 mm. |
Euphorbia radians |
Euphorbia cumulicola |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting year-round. |
Habitat | Pinyon-juniper woodlands, oak savannas, desert grasslands and scrub. | Sandy oak hammocks, open sandy areas behind mangroves, disturbed sandy sites. |
Elevation | 700–2500 m. (2300–8200 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AZ; TX; Mexico
|
FL |
Discussion | Euphorbia radians is widely distributed but scattered from the Sonoran and Chihuahuan deserts south to Oaxaca in Mexico. The species is distinct among species in sect. Poinsettia in the flora area in its precocious habit, often flowering before the leaves emerge. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia cumulicola could be confused with E. bombensis, both of which are widespread in Florida, but there the latter occurs on beaches close to the ocean, whereas E. cumulicola is not a beach-inhabiting species but occurs in more protected sandy habitats such as hammocks or stabilized dunes behind mangroves. Also, E. bombensis has fleshier leaves and larger seeds, and is more compact in habit than E. cumulicola, which is a more sprawling and densely branched plant with leaves that are usually purplish tinged along the margins. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 324. | FNA vol. 12, p. 265. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Poinsettia radians | Chamaesyce cumulicola |
Name authority | Bentham: Pl. Hartw., 8. (1839) | (Small) Oudejans: Phytologia 67: 45. (1989) |
Web links |