Euphorbia cuphosperma |
Euphorbia trachysperma |
|
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hairy-fruit spurge |
San Pedro River sandmat |
|
Habit | Herbs, annual, with taproot. | Herbs, annual, with slender taproot. |
Stems | erect, 13–20 cm, both pilose to villous and densely strigillose; branches ± straight. |
erect to ascending, 10–55 cm, glabrous. |
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 distinct, narrowly triangular and often divided into 3–5 subulate to filiform segments, 0.8–1.9 mm, glabrous; petiole 1.2–3.1 mm, glabrous; blade oblong, elliptic, or ovate, 12–43 × 3–14 mm, base subsymmetric to asymmetric, rounded, attenuate, or with one side hemicordate and other side rounded, margins usually serrulate, rarely entire on some leaves or portion of blade, apex obtuse to acute, surfaces often with red blotch in center, glabrous; pinnately veined, often only midvein conspicuous. |
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. |
oblong, campanulate, or funnel-shaped, 1.5–2.6 × 1.1–2.3 mm, glabrous; glands 4, green to yellowish or tinged with red, subcircular to oblong, 0.4–0.7 × 0.5–1 mm; appendages absent or white, often forming narrow rim or oblong to ovate, 0–0.8 × 1.2 mm, distal margin entire. |
Staminate flowers | 3–5. |
50–60. |
Pistillate flowers | ovary pilose; styles 1.2 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.5–0.6 mm, 2-fid 1/2 length. |
Capsules | broadly ovoid, 2.2–3 × 1.9–2.7 mm, 3-lobed, pilose; columella 2–2.4 mm. |
oblate, 2.4–3.2 × 3–3.5 mm, glabrous; columella 2.3–2.5 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 brown, ovoid, 4-angled in cross section, abaxial keel well developed, 1.9–2.3 × 1.3–1.4 mm, finely dimpled and papillate. |
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 nodes; peduncle 1.4–2.4 mm. |
2n | = 56. |
|
Euphorbia cuphosperma |
Euphorbia trachysperma |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting late summer–early winter. |
Habitat | Open montane and canyon forests, pinyon-juniper forests, montane grasslands, stream beds, disturbed habitats. | Desert scrub, desert grasslands, mesquite woodlands. |
Elevation | 800–2000 m. (2600–6600 ft.) | 200–1200 m. (700–3900 ft.) |
Distribution |
AZ; NM; Mexico; Central America (Guatemala)
|
AZ; Mexico (Baja California Sur, Sonora) |
Discussion | Euphorbia trachysperma may be expected in extreme southwestern New Mexico given the close proximity of some collections in southeastern Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 319. | FNA vol. 12, p. 291. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | E. dentata var. cuphosperma, Poinsettia cuphosperma | Chamaesyce trachysperma |
Name authority | (Engelmann) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 73. (1862) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) |
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