Euphorbia exstipulata |
Euphorbia parishii |
|
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square-seed spurge, squareseed or Clark Mountain spurge |
Parish's sandmat |
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Habit | Herbs, annual, with slender taproot. | Herbs or subshrubs, perennial, with thickened and often woody rootstock. |
Stems | erect, 5–26 cm, uniformly puberulent to hispidulous or glabrous; branches arcuate. |
prostrate, sometimes forming dense mounds, 10–50 cm, glabrous. |
Leaves | opposite; petiole 1–3 mm, often indistinct, glabrous or puberulent; blade linear to narrowly elliptic or ovate, 14–42 × 3–28 mm, base attenuate, margins coarsely serrate, occasionally revolute, apex acute to obtuse, abaxial surface sparsely hispidulous to strigillose, adaxial surface glabrous; midvein conspicuous. |
opposite; stipules distinct, subulate-filiform, 0.3–0.9 mm, pilose; petiole 0.3–1.2 mm, glabrous; blade usually ovate, rarely oblong, 2–7 × 1–5 mm, base usually asymmetric, rounded to hemicordate, margins entire, apex usually obtuse, rarely acute, surfaces glabrous; only midvein conspicuous. |
Involucre | turbinate to campanulate, 1.1–1.5 × 1–1.3 mm, glabrous, pilose or puberulent; involucral lobes divided into several linear lobes; glands 4(–5), yellow to pink, sessile and broadly attached, 0.2 × 0.3–0.4 mm, opening oblong to nearly circular, glabrous; appendages usually petaloid, white to pink, ovate to trapezoidal, occasionally absent, not incurved and covering glands, 0.2–0.4 × 0.3–0.8 mm, entire, undulate, or conspicuously divided into triangular segments, glabrous. |
obconic to campanulate, 1–1.4 × 0.9–1.3 mm, glabrous except for pilose lobes; glands 4, pink to maroon, circular, 0.3–0.4 × 0.3–0.4 mm; appendages absent. |
Staminate flowers | 10–12. |
40–50. |
Pistillate flowers | ovary puberulent on keels, styles 0.8–1.1 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous; styles 0.3–0.6 mm, 2-fid 1/2 length. |
Capsules | broadly depressed-oblong to ovoid, 2.7–3.3 × 3.1–3.9 mm, puberulent (with appressed hairs usually concentrated on keels); columella 1.9–2.5 mm. |
ovoid to oblate-ovoid, 1.6–1.7 × 1.6–1.9 mm, glabrous; columella 1.2–1.5 mm. |
Seeds | white to gray or light brown, ovoid, bluntly 4-angled in cross section, 1.9–2.5 × 1.4–1.7 mm, tuberculate, often with 2 transverse ridges; caruncle 0.1 × 0.2 mm. |
whitish to light brown, ovoid, 4-angled in cross section, 1.2–1.4 × 0.6–0.8 mm, rugose or with indistinct, irregular, low transverse ridges. |
Cyathial | arrangement: terminal cymose or dichasial branches usually 1–2, occasionally reduced to monochasia, 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 similar in shape to distal leaves but smaller or highly reduced. |
|
Cyathia | peduncle 1–1.9 mm. |
solitary at distal nodes; peduncle 0.1–0.6(–2.2) mm. |
Euphorbia exstipulata |
Euphorbia parishii |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting fall–summer. |
Habitat | Desert scrub, grasslands, mesquite savannas, oak and oak-juniper woodlands. | Desert scrub, often with creosote bush, disturbed roadsides, rocky soils. |
Elevation | 800–2000 m. (2600–6600 ft.) | -90–600 m. (-300–2000 ft.) |
Distribution |
AZ; CA; NM; TX; UT; WY; Mexico (Chihuahua, Coahuila, Durango, Guanajuato, San Luis Potosí, Sonora, Zacatecas)
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CA; NV |
Discussion | Euphorbia exstipulata is native from Texas to California and northern Mexico. The species was found once in the late nineteenth century in Wyoming but has not been re-collected there. Broad-leaved plants have been segregated as var. lata, but the variation in leaf shape is continuous and no varieties are formally recognized here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia parishii is common in the Death Valley region of southern California, where it is often encountered well below sea level. The species is frequently confused with E. micromera and E. polycarpa but differs from the former in being a more robust plant with larger cyathia and from the latter in lacking involucral gland appendages. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 322. | FNA vol. 12, p. 280. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | E. exstipulata var. lata | Chamaesyce parishii, E. polycarpa var. parishii |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) | Greene: Bull. Calif. Acad. Sci. 2: 56. (1886) |
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