Euphorbia arizonica |
Euphorbia garberi |
|
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Arizona sandmat, Arizona spurge |
Garber's sandmat |
|
Habit | Herbs, annual or short-lived perennial, with slender to slightly thickened taproot. | Herbs, perennial, with moderately thickened rootstock. |
Stems | erect to ascending, 10–30 cm, uniformly pilose with glistening hairs. |
ascending, sometimes slightly woody at base, not wiry, 1–3 mm diam., 15–50 cm, canescent. |
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. |
opposite; stipules distinct or connate at base, triangular-subulate, apex divided into 2–5 subulate to subulate-filiform segments, 0.5–0.7 mm, pilose; petiole 0.5–1.1 mm, pilose; blade ovate to oblong-elliptic, 4–9(–15) × 3–6 mm, base asymmetric, obtuse to rounded, margins usually entire, rarely very sparsely serrulate, apex usually obtuse to rounded, occasionally acute to apiculate, surfaces canescent; 3-veined from base, only midvein conspicuous. |
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. |
turbinate to campanulate, 0.6–0.9 × 0.5–0.9 mm, pilose; glands 4, brown, slightly concave, elliptic to subcircular, 0.1–0.3 × 0.2–0.4 mm; appendages white to pink, as narrow rim along gland, (0–)0.1–0.2 × 0.3–0.5 mm, surfaces pilose, distal margin entire or crenulate. |
Staminate flowers | 5–12. |
8–20. |
Pistillate flowers | ovary pilose, styles 0.5–0.6 mm, 2-fid 1/2 length. |
ovary pilose; styles 0.6–0.7 mm, 2-fid 1/2 length. |
Capsules | broadly ovoid to subglobose, 1.4–1.8 mm diam., pilose; columella 1.1–1.4 mm. |
subglobose to broadly ovoid, 1.1–1.6 × 1.3–2.1 mm, pilose; columella 1.1–1.6 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. |
gray to reddish brown, oblong-ovoid, 4-angled in cross section, 1–1.2 × 0.6–0.8 mm, flat or obscurely wrinkled. |
Cyathia | solitary at distal nodes; peduncle 0.7–3.6 mm. |
solitary at nodes of short, axillary branches; peduncle 0.2–0.4 mm. |
Euphorbia arizonica |
Euphorbia garberi |
|
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. | Beach dunes, coastal rock barrens, disturbed uplands and pine rocklands. |
Elevation | 100–1400 m. (300–4600 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Sonora)
|
FL |
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.) |
Euphorbia garberi appears to be an interspecific hybrid, but its parentage is not entirely clear (Y. Yang and P. E. Berry 2011). The taxon is closely related to E. blodgettii, E. porteriana, and E. serpens. It is restricted to Collier, Miami-Dade, and Monroe counties in southern Florida and is federally listed as threatened due to impacts from habitat loss, fire suppression, and invasive species. A. Herndon (1993) synonymized E. porteriana var. keyensis under E. garberi because of its uniformly pilose capsules, and that treatment is followed here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 260. | FNA vol. 12, p. 268. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce arizonica | Chamaesyce adicioides, C. brachypoda, C. garberi, C. keyensis, C. mosieri, C. porteriana var. keyensis, E. porteriana var. keyensis |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859) | Engelmann ex Chapman: Fl. South. U.S. ed. 2, 646. (1883) |
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