Euphorbia setiloba |
Euphorbia wrightii |
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fringe spurge, shaggy spurge, Yuma sandmat |
Wright's spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, perennial with cylindric rootstock or elongated tubers. |
Stems | prostrate, mat-forming, 5–50 cm, villous with glistening glandular hairs. |
erect, branched, densely clumped, previous year’s dead stems often persistent, 20–50 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. |
alternate, persisting, spreading or ascending; stipules 0.1–0.3 mm; petiole absent; blade linear to linear-filiform, (17–)20–40 × 1–2.5 mm, base cuneate, slightly sheathing stem, margins entire, apex broadly acute to rounded, abaxial surface glabrous or sparsely villous, adaxial surface glabrous; venation obscure, only midvein conspicuous on wider leaves. |
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. |
campanulate, 1.5–2 × 1.8–2.5 mm, pilose; glands 5, green, broadly elliptic, 0.7–0.8 × 1 mm; appendages white to pink, orbiculate, 0.5–1 × 1.3–1.8 mm, coarsely erose. |
Staminate flowers | 3–7. |
20–25. |
Pistillate flowers | ovary villous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
ovary strigose to tomentose; styles 1 mm, 2-fid at apex. |
Capsules | subglobose to ovoid, 1–1.2 mm diam., villous; columella 0.9–1.1 mm. |
depressed-globose, 1 locule usually aborting, 2.5(–3) × 2.7–3.3(–5) mm, sparsely tomentose; columella 2.6–3 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. |
gray-green to gray-brown, globose-ovoid, 2.2–2.9 × 1.8–2 mm, shallowly and obscurely pitted; caruncle absent. |
Cyathia | solitary at distal nodes, nodes often congested toward tips of branches; peduncle 0.2–1.6 mm. |
usually in terminal dichasia, rarely pleiochasia; peduncle (3–)5–15 mm, all peduncles and cyathia persistent on plant, glabrous. |
Euphorbia setiloba |
Euphorbia wrightii |
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Phenology | Flowering nearly year-round in response to sufficient moisture. | Flowering and fruiting spring–fall. |
Habitat | Desert scrub, blackbrush scrub, Joshua tree woodlands, grasslands, often in sandy areas. | Open grasslands and uplands, often on limestone outcrops. |
Elevation | 20–1600 m. (100–5200 ft.) | 500–1000 m. (1600–3300 ft.) |
Distribution |
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Baja California Sur, Chihuahua, Durango, Sinaloa, Sonora)
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TX; Mexico (Coahuila) |
Discussion | Within the flora area, Euphorbia wrightii is endemic to the western Edwards Plateau and adjacent rolling plains in western Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 288. | FNA vol. 12, p. 251. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Chamaesyce setiloba | |
Name authority | Engelmann: in War Department [U.S.], Pacif. Railr. Rep. 5(2): 364. (1857) | Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 2(4): 174. (1857) |
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