Euphorbia setiloba |
Euphorbia bifurcata |
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fringe spurge, shaggy spurge, Yuma sandmat |
fork spurge |
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Habit | Herbs, annual, with slender taproot. | Herbs, annual, with slender, fibrous taproot. |
Stems | prostrate, mat-forming, 5–50 cm, villous with glistening glandular hairs. |
erect, 20–70 cm, glabrous or with few scattered spreading hairs; branches arcuate, branching appearing dichotomous. |
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. |
usually alternate, occasionally opposite at proximalmost node; petiole 15–49 mm, glabrous; blade usually ovate, rarely oblong or elliptic, 13–54 × 7–38 mm, base usually rounded to broadly cuneate, rarely truncate, margins finely serrulate, apex obtuse, surfaces glabrous or with few scattered hairs; venation pinnate, midvein prominent. |
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. |
tubular or obconic, 1–1.7 × 0.7–1.4 mm, glabrous except for few hairs on lobes; involucral lobes divided into several linear, smooth lobes; glands 1(–3), greenish, sessile and broadly attached, 0.3–0.4 × 0.4–0.8 mm, opening oblong to subcircular, glabrous; appendages petaloid, white, elliptic, oblong, transversely oblong, or forming thin, lunate rim on gland margin, not incurved and covering glands, 0.3–0.9 × 0.6–1.3 mm, entire, undulate or slightly lobed, glabrous. |
Staminate flowers | 3–7. |
20–30. |
Pistillate flowers | ovary villous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.6–1 mm, 2-fid 1/2 length. |
Capsules | subglobose to ovoid, 1–1.2 mm diam., villous; columella 0.9–1.1 mm. |
oblate, 2.8–3.1 × 3.6–4.5 mm, glabrous; columella 1.9–2.4 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. |
brown to blackish, ovoid, rounded in cross section, 1.9–2.4 × 1.5–1.8 mm, irregularly and coarsely tuberculate; caruncle absent or rudimentary. |
Cyathia | solitary at distal nodes, nodes often congested toward tips of branches; peduncle 0.2–1.6 mm. |
peduncle 0.9–3.5(–6.2) mm. |
Cyathial | arrangement: terminal dichasial branches 2, few-branched (weakly defined); pleiochasial bracts 2–3, opposite or whorled, wholly green, similar in shape and size to distal leaves; dichasial bracts smaller than distal leaves, often white at base. |
|
Euphorbia setiloba |
Euphorbia bifurcata |
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Phenology | Flowering nearly year-round in response to sufficient moisture. | Flowering and fruiting summer–fall. |
Habitat | Desert scrub, blackbrush scrub, Joshua tree woodlands, grasslands, often in sandy areas. | Riparian areas with cottonwoods and willows, pinyon pine woodlands, pine-oak forests, Douglas fir forests with pines. |
Elevation | 20–1600 m. (100–5200 ft.) | 1900–2300 m. (6200–7500 ft.) |
Distribution |
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Baja California Sur, Chihuahua, Durango, Sinaloa, Sonora)
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NM; TX; Mexico; Central America (Guatemala) |
Discussion | Euphorbia bifurcata is found in the mountains of southern New Mexico (Doña Ana, Grant, Lincoln, Otero, and Sierra counties) and trans-Pecos Texas (Brewster, Jeff Davis, and Presidio counties). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 288. | FNA vol. 12, p. 319. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Poinsettia |
Sibling taxa | ||
Synonyms | Chamaesyce setiloba | |
Name authority | Engelmann: in War Department [U.S.], Pacif. Railr. Rep. 5(2): 364. (1857) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 190. (1859) |
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