Euphorbia setiloba |
Euphorbia simulans |
|
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fringe spurge, shaggy spurge, Yuma sandmat |
mimicking sandmat, similar spurge |
|
Habit | Herbs, annual, with slender taproot. | Herbs, annual or short-lived perennial, with usually slender, occasionally slightly thickened, rootstock. |
Stems | prostrate, mat-forming, 5–50 cm, villous with glistening glandular hairs. |
prostrate to reclining, 5–40 cm, glabrous. |
Leaves | opposite; stipules distinct, filiform, rudimentary to 0.2 mm, glabrous or sparsely villous with glistening glandular hairs; petiole 0.5–1.5 mm, villous; blade oblong, ovate, or elliptic, 3–7 × 2–4 mm, base asymmetric, rounded, margins entire, apex obtuse, surfaces villous; weakly 3-veined from base, commonly only midvein conspicuous. |
opposite; stipules distinct, subulate, 0.5–0.7 mm, glabrous; petiole 0.7–1.3 mm, glabrous; blade orbiculate, oval, to shortly oblong, 1–3.2 × 1.5–5 mm, base subsymmetric, rounded, margins entire, apex usually rounded, occasionally emarginate, surfaces glabrous; venation obscure, only midvein conspicuous. |
Involucre | campanulate or urceolate, 0.7–1 × 0.5–0.8 mm, villous; glands 4, red to pink, oblong to slightly reniform, 0.1–0.2 × 0.2–0.3 mm; appendages white to pink, deeply incised into 3–6 triangular to subulate, attenuate, acute segments, 0.3–0.6 × 0.6–1 mm, segments entire. |
turbinate to campanulate, 0.8–1.2 × 0.7–1 mm, glabrous; glands 4, red to purple, slightly concave, elliptic, 0.2–0.3 × 0.4–0.5 mm; appendages absent. |
Staminate flowers | 3–7. |
15–36. |
Pistillate flowers | ovary villous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.2–0.3 mm, 2-fid nearly entire length. |
Capsules | subglobose to ovoid, 1–1.2 mm diam., villous; columella 0.9–1.1 mm. |
broadly ovoid, 1.3–1.8 × 1.5–2 mm, glabrous; columella 1.1–1.4 mm. |
Seeds | pink to light gray, narrowly ovoid, 4-angled in cross section, 0.8–1 × 0.5–0.6 mm, dimpled or with faint transverse ridges that do not pass through abaxial keel. |
whitish, reddish brown beneath coat, oblong, 4-angled in cross section, 1.5–2 × 1.3–1.8 mm, with 5–7 faint transverse ridges or wrinkles. |
Cyathia | solitary at distal nodes, nodes often congested toward tips of branches; peduncle 0.2–1.6 mm. |
solitary at distal nodes; peduncle 0.3–0.7 mm. |
2n | = 28. |
|
Euphorbia setiloba |
Euphorbia simulans |
|
Phenology | Flowering nearly year-round in response to sufficient moisture. | Flowering and fruiting year-round. |
Habitat | Desert scrub, blackbrush scrub, Joshua tree woodlands, grasslands, often in sandy areas. | Desert scrub, mountains, hills, canyons, arroyos, flats, roadsides, clay, sandy, gravelly, and rocky soils. |
Elevation | 20–1600 m. (100–5200 ft.) | 600–1300 m. (2000–4300 ft.) |
Distribution |
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Baja California Sur, Chihuahua, Durango, Sinaloa, Sonora)
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TX; Mexico (Chihuahua, Coahuila) |
Discussion | Euphorbia simulans, which in the flora area is known only from Brewster, Hudspeth, and Presidio counties, is difficult to distinguish in the field from the sympatric E. theriaca var. theriaca, because they are mainly distinguished by seed morphology. The latter has smaller seeds with (two or) three (or four) prominent transverse ridges, whereas E. simulans has larger seeds that are slightly wrinkled. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 288. | FNA vol. 12, p. 289. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce setiloba | E. polycarpa var. simulans, Chamaesyce simulans |
Name authority | Engelmann: in War Department [U.S.], Pacif. Railr. Rep. 5(2): 364. (1857) | (L. C. Wheeler) Warnock & M. C. Johnston: SouthW. Naturalist 5: 170. (1960) |
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