Euphorbia cuphosperma |
Euphorbia gracillima |
|
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hairy-fruit spurge |
Mexican 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, 5–25 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, subulate-filiform, entire, 0.3–0.5 mm, glabrous; petiole 0.4–0.9 mm, glabrous; blade narrowly oblong to linear, often slightly falcate, 2–15 × 0.3–0.8 mm, base symmetric to subsymmetric, rounded to attenuate, margins entire, thickened and often revolute, apex acute to obtuse, surfaces glabrous; 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. |
turbinate, 0.4–0.5 × 0.4–0.6 mm, glabrous; glands 4, yellow to pink, oblong to slightly reniform, (0–)0.1–1 × 0.1–0.2 mm; appendages white to pink, ovate to oblong, 0.2–0.4 × 0.1–0.3 mm, distal margin usually entire, rarely emarginate. |
Staminate flowers | 3–5. |
5–12. |
Pistillate flowers | ovary pilose; styles 1.2 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.1–0.2 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. |
broadly ovoid, 1.1–1.4 mm diam., glabrous; columella 0.8–1.1 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. |
orange to tan or reddish brown, narrowly ovoid, 4-angled in cross section, 0.9–1.1 × 0.5–0.6 mm, smooth. |
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 0.1–0.9 mm. |
2n | = 56. |
|
Euphorbia cuphosperma |
Euphorbia gracillima |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting late summer–fall. |
Habitat | Open montane and canyon forests, pinyon-juniper forests, montane grasslands, stream beds, disturbed habitats. | Rocky slopes and dry washes in desert scrub. |
Elevation | 800–2000 m. (2600–6600 ft.) | 600–900 m. (2000–3000 ft.) |
Distribution |
AZ; NM; Mexico; Central America (Guatemala)
|
AZ; Mexico (Chihuahua, Jalisco, Sinaloa, Sonora) |
Discussion | Euphorbia gracillima occurs from south-central Arizona (Pima and Pinal counties) south through northwestern Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 319. | FNA vol. 12, p. 270. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | E. dentata var. cuphosperma, Poinsettia cuphosperma | Chamaesyce gracillima |
Name authority | (Engelmann) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 73. (1862) | S. Watson: Proc. Amer. Acad. Arts 21: 438. (1886) |
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