Euphorbia cuphosperma |
Euphorbia nephradenia |
|
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hairy-fruit spurge |
Paria spurge, Utah spurge |
|
Habit | Herbs, annual, with taproot. | Herbs, annual, with slender little-branched taproot. |
Stems | erect, 13–20 cm, both pilose to villous and densely strigillose; branches ± straight. |
erect to ascending, branched, dichotomous distally and slightly angled, 4–25 cm, glabrous or sparsely strigillose. |
Leaves | usually opposite, occasionally alternate at distal nodes; petiole 3–15 mm, pilose; blade narrowly to broadly elliptic, or lanceolate to ovate, 30–80 × 10–15 mm, base cuneate to rounded, margins coarsely crenate-dentate, strigose, revolute to nearly flat, apex broadly acute to acuminate, or obtuse, abaxial surface pilose, adaxial surface sparsely strigose-hirsute; venation pinnate, midvein prominent. |
opposite; stipules 0.1–0.2 mm; petiole 2–6 mm, glabrous or sparsely strigillose; blade usually linear- to narrowly-elliptic, occasionally ovate to obovate, 14–42 × 3–10 mm, progressively narrower distally, base attenuate, margins entire, apex usually acute, rarely obtuse, surfaces glabrous or sparsely strigillose; venation inconspicuous. |
Involucre | campanulate to slightly cylindric, 2.3 × 1.2 mm, glabrous; involucral lobes divided into several linear, smooth lobes; gland 1, yellow-green, stipitate, clavate, 1–1.2 × 0.8–0.9 mm, opening bilabiate and oblong, glabrous; appendages absent. |
campanulate, 1–1.1 × 1.2–1.4 mm, strigillose at least toward apex; glands 5, green-yellow, oblong, 0.4–0.6 × 0.7–1 mm; appendages whitish to yellow-green, lunate to broadly ovate, 0.2–0.5 × 0.7–1.1 mm, entire or slightly crenulate. |
Staminate flowers | 3–5. |
25–30. |
Pistillate flowers | ovary pilose; styles 1.2 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.7–1 mm, 2-fid at apex. |
Capsules | broadly ovoid, 2.2–3 × 1.9–2.7 mm, 3-lobed, pilose; columella 2–2.4 mm. |
oblate to subglobose, 2.9–3.2 × 3.2–3.4 mm, glabrous; columella 2.8–3.1 mm. |
Seeds | gray-brown to pale gray, pyramidally ovoid, angular in cross section, 2.3–2.6 × 2.4–2.6 mm, coarsely tuberculate, tubercles in 2 transverse rows; caruncle 0.2–0.4 mm. |
light gray to whitish, oblong-ovoid, rounded in cross section, 2.3–2.6 × 1.3–1.5 mm, dimpled and rugulose; caruncle absent. |
Cyathial | arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched; pleiochasial bracts 2–4, often whorled, wholly green or paler green at base, similar in shape and size to distal leaves or slightly narrower; dichasial bracts highly reduced. |
|
Cyathia | peduncle 0.5–0.8 mm. |
solitary at distal bifurcations of stems; peduncle 0.6–2.4 mm, glabrous or strigillose. |
2n | = 56. |
|
Euphorbia cuphosperma |
Euphorbia nephradenia |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting spring–summer. |
Habitat | Open montane and canyon forests, pinyon-juniper forests, montane grasslands, stream beds, disturbed habitats. | Saltbush, blackbrush, Ephedra-dominated scrub and desert communities. |
Elevation | 800–2000 m. (2600–6600 ft.) | 1100–1500 m. (3600–4900 ft.) |
Distribution |
AZ; NM; Mexico; Central America (Guatemala)
|
CO; UT |
Discussion | Euphorbia nephradenia is the only species of the genus endemic to the Colorado Plateau of Utah and adjacent Colorado. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 319. | FNA vol. 12, p. 249. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | E. dentata var. cuphosperma, Poinsettia cuphosperma | |
Name authority | (Engelmann) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 73. (1862) | Barneby: Leafl. W. Bot. 10: 314. (1966) |
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