Euphorbia arizonica |
Euphorbia peplus |
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Arizona sandmat, Arizona spurge |
petty spurge |
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Habit | Herbs, annual or short-lived perennial, with slender to slightly thickened taproot. | Herbs, annual, with taproot. |
Stems | erect to ascending, 10–30 cm, uniformly pilose with glistening hairs. |
erect, unbranched or branched, 5–30 cm, glabrous. |
Leaves | opposite; stipules distinct, deltate, (0–)0.1 mm, glabrous or with few scattered hairs; petiole 0.4–1.5 mm, pilose with glistening hairs; blade usually ovate, rarely elliptic, 3–11 × 2–7 mm, base asymmetric, one side cuneate to rounded, other side rounded to strongly cordate, margins entire, apex obtuse or acute, surfaces pilose with glistening hairs; 3-veined from base but usually only midvein conspicuous. |
petiole 1–10 mm; blade obovate, oblong, or suborbiculate, 5–25 × 4–15 mm, base attenuate or cuneate, margins entire, apex obtuse, surfaces glabrous; venation pinnate, midvein prominent. |
Involucre | urceolate, 1.1–1.3 × 0.5–0.9 mm, glabrous or pilose with glistening hairs; glands 4, dark maroon, usually oblong to reniform, rarely almost circular, 0.2 × 0.2–0.4 mm; appendages white to pink, oblong, flabellate, oblong, or elliptic, 0.3–0.6 × 0.6–0.9 mm, distal margin entire or crenulate. |
cupulate to slightly turbinate, 0.6–1.1 × 0.7–0.9 mm, glabrous; glands 4, elliptic, 0.2–0.3 × 0.5–0.6 mm; horns slightly convergent to divergent, 0.4–0.6 mm. |
Staminate flowers | 5–12. |
10–15. |
Pistillate flowers | ovary pilose, styles 0.5–0.6 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.1–0.2 mm, 2-fid. |
Capsules | broadly ovoid to subglobose, 1.4–1.8 mm diam., pilose; columella 1.1–1.4 mm. |
subglobose, 1.3–2 × 1.5–2.2 mm, slightly 3-lobed; cocci rounded, with 2 low longitudinal wings, smooth, glabrous; columella 1.1–1.3 mm. |
Seeds | gray to light brown, ovoid, 4-angled in cross section, 0.9–1.1 × 0.5–0.6 mm, rugose with 2–5 irregular transverse ridges that sometimes pass through abaxial keel. |
whitish or grayish, subovoid, 1–1.6 × 0.6–1 mm, abaxial faces regularly large-pitted (appearing almost alveolate), adaxial faces longitudinally sulcate; caruncle deciduous, conic, 0.2–0.5 × 0.2–0.7 mm. |
Cyathia | solitary at distal nodes; peduncle 0.7–3.6 mm. |
peduncle 0.4–1.1 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3–5, usually 2–8 times 2-branched, 1st branching level rarely 3-furcate; pleiochasial bracts similar in shape to and slightly larger than distal leaves; dichasial bracts distinct, ovate to obovate, base obtuse, margins entire, apex obtuse, usually mucronate; axillary cymose branches 0–3. |
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Euphorbia arizonica |
Euphorbia peplus |
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Phenology | Flowering and fruiting year-round in response to sufficient moisture. | Flowering and fruiting year-round. |
Habitat | Washes and rocky slopes, sometimes on limestone, desert scrub communities often with creosote-bush, riparian forests, mesquite woodlands, oak chaparral. | Edges of gardens, weedy flower beds, roadsides, waste places, open ground near forests. |
Elevation | 100–1400 m. (300–4600 ft.) | 0–1500 m. (0–4900 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Sonora)
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AL; AZ; CA; CO; CT; DE; IA; ID; IL; IN; KY; LA; MA; MD; ME; MI; MT; NC; ND; NH; NJ; NM; NV; NY; OH; OR; PA; RI; TN; TX; UT; VA; VT; WA; WI; WV; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK; Europe; w Asia [Introduced in North America; introduced also in Mexico, West Indies, Bermuda, Central America, South America, Africa, Atlantic Islands, Indian Ocean Islands, Pacific Islands, Australia]
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Discussion | Euphorbia arizonica is distinctive and easily recognized by its glistening, translucent hairs that appear somewhat glutinous and are most apparent on the stems. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 260. | FNA vol. 12, p. 307. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Chamaesyce arizonica | Esula peplus, Galarhoeus peplus, Tithymalus peplus |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859) | Linnaeus: Sp. Pl. 1: 456. (1753) |
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