Euphorbia radians |
Euphorbia rosescens |
|
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sun spurge |
rosy-pink spurge, scrub spurge |
|
Habit | Herbs, perennial, with moniliform tuberous rootstock. | Herbs, perennial, with thickened rootstock. |
Stems | erect, 5–20(–30) cm, usually glabrous, occasionally puberulent; branches ± straight. |
erect or ascending, 15–45 cm. |
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. |
petiole indistinct, blade narrowly elliptic, elliptic, narrowly oblong, or obovate, 25–55 × 5–21 mm, thick and fleshy, base attenuate, apex acute or mucronulate; only midvein evident. |
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. |
obconic to campanulate, 2.4–3.6 × 2.5–3.6 mm, lobes ovate to oblong, 0.7–1 mm, ciliate; glands green to yellow, oblong or trapezoidal, 0.9–1.7 × 1.9–2.5 mm, distal margins crenulate-erose. |
Staminate flowers | 20–25. |
25. |
Pistillate flowers | ovary glabrous or puberulent, styles 3–4 mm, 2-fid 1/2 to nearly entire length. |
mature gynophore not seen, styles connate 1/2 length, 3.3–3.6 mm. |
Capsules | depressed-globose, 3.8–5 × 4–5 mm, 3-lobed, glabrous or puberulent; columella 3.6–4.5 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. |
not seen. |
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. |
arrangement: terminal pleiochasial branches 3, 7–16 cm, 4–7 times 2-branched; pleiochasial bracts ovate to oblong, 17–31 × 13–14 mm, margins entire, apex acute, often also mucronulate; dichasial bracts ovate or lanceolate, 6–18 × 8–12 mm, margins entire, apex acute, often also mucronate; axillary cymose branches 1–2. |
Cyathia | peduncle 2–5.5 mm. |
peduncle 3.9–6.8 mm. |
Mature | capsules not seen. |
|
Euphorbia radians |
Euphorbia rosescens |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring–summer, rarely fall. |
Habitat | Pinyon-juniper woodlands, oak savannas, desert grasslands and scrub. | Xeric oak and pine scrub, mostly on white sands, disturbed habitats. |
Elevation | 700–2500 m. (2300–8200 ft.) | 20–50 m. (100–200 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 rosescens is a narrow-endemic, gap-specialist known only from the southern portion of the Lake Wales Ridge in Highlands County. Based on leaf characteristics, it appears to be most similar to E. telephioides. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 324. | FNA vol. 12, p. 316. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Nummulariopsis |
Sibling taxa | ||
Synonyms | Poinsettia radians | |
Name authority | Bentham: Pl. Hartw., 8. (1839) | E. L. Bridges & Orzell: Lundellia 5: 71, fig. 4. (2002) |
Web links |