Euphorbia antisyphilitica |
Euphorbia micromera |
|
---|---|---|
candelilla, wax plant |
desert spurge, Sonoran sandmat, tiny sandmat |
|
Habit | Shrubs, with much-branched, fleshy rootstock. | Herbs, annual, with slender taproot. |
Stems | erect, few branched, 25–50(–100) cm, glabrous or puberulent, pencil-like, in age covered with flaky, exfoliating layer of wax. |
prostrate, mat-forming, 5–35 cm, glabrous or shortly pilose. |
Leaves | alternate usually caducous, sometimes persisting; stipules 0.4–0.5 mm; petiole absent; blade ovate to deltate-subulate, 2.5–4 × 1 mm, thick, fleshy, base usually rounded and swollen, rarely cuneate, margins entire, apex acute, surfaces puberulent, adaxial sometimes canescent; venation inconspicuous. |
opposite; stipules distinct, subulate, 0.2–0.4 mm, pilose; petiole 0.5–1.2 mm, glabrous or pilose; blade ovate to elliptic, 6–15 × 2–4 mm, base asymmetric, one side cuneate to rounded, other side rounded, margins entire, apex obtuse, surfaces glabrous or pilose; venation obscure or only midvein conspicuous. |
Involucre | campanulate, 1.6–2.2 × 1.6–1.9 mm, puberulent to canescent; glands 5, pinkish, narrowly oblong to reniform, 0.3–0.4 × 0.8–1 mm; appendages white to pink, ovate, oblong, or transversely oblong, 1.3–2.5 × 1.4–2.5 mm, usually erose, rarely entire. |
campanulate, 0.4–0.6 × 0.5–0.9 mm, glabrous or pilose; glands 4, red, circular to oblong, 0.1 × 0.1–0.2 mm; appendages absent. |
Staminate flowers | 50–70. |
2–5. |
Pistillate flowers | ovary glabrous; styles 0.9–1.1 mm, 2-fid nearly entire length. |
ovary usually glabrous, rarely pilose; styles 0.1–0.2 mm, 2-fid at apex. |
Capsules | oblong to ovoid, 3.9–4.2 × 3.6–3.9 mm, glabrous; columella 3.1–3.3 mm. |
oblong, 1.3–1.5 × 1.1–1.3 mm, usually glabrous, rarely pilose; columella 1–1.2 mm. |
Seeds | whitish gray, narrowly ovoid, 2.4–3.1 × 1.4–1.6 mm, irregularly rugose-tuberculate; caruncle crescent-shaped, 0.3–0.6 × 0.6–0.8 mm. |
light gray, narrowly ovoid, 4-angled in cross section, 0.9–1 × 0.5–0.6 mm, smooth to slightly rugose or with 1–4 faint transverse ridges that do not pass through abaxial keel. |
Cyathia | in axillary congested cymes, near branch tips or solitary at distal nodes; peduncle 0–1 mm, lanulose. |
solitary at distal nodes; peduncle 0.4–1.4 mm. |
Euphorbia antisyphilitica |
Euphorbia micromera |
|
Phenology | Flowering and fruiting year-round in response to sufficient rainfall. | Flowering nearly year-round in response to sufficient rainfall. |
Habitat | Desert scrub, frequently on limestone substrates. | Desert scrub, riparian woods with ash and willow, saltbush scrub, Joshua tree woodlands and grasslands, often in sandy or gravelly areas. |
Elevation | 100–1200 m. (300–3900 ft.) | -20–1800 m. (-100–5900 ft.) |
Distribution |
NM; TX; Mexico
|
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Sonora)
|
Discussion | Euphorbia antisyphilitica is the only pencil-stemmed species of Euphorbia occurring in the flora area. The species is characteristic of the Chihuahuan Desert scrub of Mexico from Chihuahua and Coahuila south to Hidalgo and Querétaro, and barely enters into the United States in southern New Mexico (Doña Ana and Lincoln counties) and southwest (Brewster, Hudspeth, Presidio, and Terrell counties) and south (Starr and Webb counties) Texas. The stems are covered in a conspicuous coat of exfoliating wax, and the plants historically have been harvested for this product, although the practice is much less prevalent now. The specific epithet refers to its traditional medicinal use in treating sexually transmitted infections. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 243. | FNA vol. 12, p. 278. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce micromera | |
Name authority | Zuccarini: Flora 15(2, Beibl.): 58. (1832) | Boissier: Proc. Amer. Acad. Arts 5: 171. (1861) |
Web links |