Euphorbia florida |
Euphorbia acuta |
|
---|---|---|
Chiricahua Mountain sandmat |
point sandmat |
|
Habit | Herbs, annual, with slender taproot. | Herbs, perennial, with strongly thickened rootstock. |
Stems | erect, 15–60 cm, usually glabrous, rarely puberulent. |
ascending to erect, 5–30 cm, uniformly and densely canescent or sericeous. |
Leaves | opposite; stipules distinct, divided into 3–4 subulate-filiform divisions, 0.4–1.6 mm, usually glabrous, rarely puberulent; petiole 0.5–2.5 mm, glabrous; blade usually linear, rarely to narrowly elliptic, 10–40(–60) × 0.5–2.5 mm, base symmetric, attenuate, margins serrulate, often revolute, apex acute, surfaces usually glabrous, rarely puberulent; obscurely pinnately veined. |
opposite; stipules deciduous, sometimes appearing absent, distinct, brown, linear-subulate, thin, 0.3–0.8 mm, canescent; petiole 0.4–1.2 mm, moderately to densely canescent; blade ovate to lanceolate, 6–20 × 3–8 mm, base subsymmetric, rounded to cuneate, margins entire, strongly involute, apex long-acuminate, spinulose, abaxial surface canescent to densely sericeous, adaxial surface glabrous or sparsely canescent; 3-veined from base but only midvein conspicuous. |
Involucre | obconic, 1.7–2.4 × 1.5–2.1 mm, glabrous; glands 4, greenish yellow to slightly pink, circular to oblong, 0.4–0.5 × 0.4–0.6 mm; appendages white to pink, obovoid, circular, flabellate, or oblong, 0.8–2.9 × 1–2.8 mm, distal margin entire. |
turbinate to urceolate, 2–2.6 × 1.7–2.5 mm, villous to lanate; glands 4, yellow-green to orange or red, slightly concave, oblong-elliptic, 0.2–0.4 × 0.6–1.5 mm; appendages white, flabellate, 1.1–2.1 × 0.2–0.6 mm, distal margin shallowly and irregularly toothed. |
Staminate flowers | 25–35. |
20–25. |
Pistillate flowers | ovary glabrous; styles 0.8–1.4 mm, 2-fid entire length. |
ovary strigose, pubescent to villous; styles 0.6–0.9 mm, 2-fid 1/2 length. |
Capsules | oblate, 2.2–2.5 × 2.7–3.1 mm, glabrous; columella 1.8–2.1 mm. |
subglobose to broadly ovoid, 2.8–3.7 mm diam., strigose, pubescent to villous; columella 2.3–3 mm. |
Seeds | light gray to light brown, ovoid, slightly 4-angled in cross section, 1.6–2 × 1.3–1.7 mm, with 2 or 3 well-developed transverse ridges. |
white, ovoid, 4-angled in cross section, 2.2–2.6 × 1.1–1.4 mm, smooth to finely reticulate. |
Cyathia | solitary at nodes or in small, cymose clusters at branch tips; peduncle 1.2–8.1 mm. |
solitary at distal nodes; peduncle 1.3–3.2 mm. |
2n | = 28, 48, 56. |
|
Euphorbia florida |
Euphorbia acuta |
|
Phenology | Flowering and fruiting summer–late fall. | Flowering and fruiting spring–fall. |
Habitat | Sandy flats, gravelly washes, rocky hillsides, talus slopes, desert scrub, desert grasslands, mesquite woodlands, rarely oak woodlands. | Desert scrub, grasslands, oak-juniper savannas, limestone, rocky, sandy, or clay soils. |
Elevation | 600–1300 m. (2000–4300 ft.) | 400–1900 m. (1300–6200 ft.) |
Distribution |
AZ; Mexico (Sinaloa, Sonora)
|
NM; TX; Mexico (Chihuahua, Coahuila) |
Discussion | Euphorbia florida is known in the flora area from Coconino County south to the Mexican border (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia acuta is easily distinguished in the field by its relatively large, strongly involute, hairy, and acutely pointed leaves. The name Euphorbia acuta Engelmann has been proposed for conservation against the earlier name E. acuta Bellardi ex Colla (P. E. Berry et al. 2011). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 267. | FNA vol. 12, p. 259. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce florida | Chamaesyce acuta, E. acuta var. stenophylla, E. georgei |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) — name proposed for conservation |
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