Euphorbia hyssopifolia |
Euphorbia acuta |
|
---|---|---|
hyssopleaf sandmat |
point sandmat |
|
Habit | Herbs, annual, with taproot. | Herbs, perennial, with strongly thickened rootstock. |
Stems | erect to ascending, 80 cm, sparsely to densely pilose or pilose-crinkled proximally, usually glabrous distally. |
ascending to erect, 5–30 cm, uniformly and densely canescent or sericeous. |
Leaves | opposite; stipules usually connate, irregularly lacerate, 0.5–1 mm, usually glabrous, occasionally with few marginal hairs; petiole 1–2 mm, glabrous; blade lanceolate to oblong or falcate, 8–35 × 7–15 mm, base asymmetric, rounded, margins serrulate, apex broadly acute, abaxial surface glabrous or sparsely pilose toward base, adaxial surface glabrous; palmately veined at base, pinnate distally. |
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, 0.9–1.1 × 0.7–0.9 mm, glabrous; glands 4(–5) (5th gland without appendage), yellow-green to maroon, elliptic to circular, 0.1–0.2 × 0.1–0.3 mm; appendages spreading, usually white or turning reddish with age, short reniform or semilunate, 0.1–0.3 × 0.2–0.6 mm, distal margin entire or slightly undulate to crenate. |
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 | 4–15. |
20–25. |
Pistillate flowers | ovary glabrous; styles 0.5–0.9 mm, 2-fid 1/2 length. |
ovary strigose, pubescent to villous; styles 0.6–0.9 mm, 2-fid 1/2 length. |
Capsules | depressed-ovoid, 1.5–1.6 × 1.7–1.8 mm, glabrous; columella 1.5–2 mm. |
subglobose to broadly ovoid, 2.8–3.7 mm diam., strigose, pubescent to villous; columella 2.3–3 mm. |
Seeds | brown to grayish white, ovoid, slightly 4-angled in cross section, abaxial faces convex, adaxial faces slightly concave to slightly convex, 1–1.4 × 0.7–1.1 mm, with 2–3 prominent transverse ridges that do not interrupt adaxial keel, or coarsely and inconspicuously pitted-reticulate. |
white, ovoid, 4-angled in cross section, 2.2–2.6 × 1.1–1.4 mm, smooth to finely reticulate. |
Cyathia | solitary or in small, cymose clusters occasionally with bractlike leaves at distal nodes or on congested, axillary branches; peduncle 0.5–2.5 mm. |
solitary at distal nodes; peduncle 1.3–3.2 mm. |
2n | = 12, 14. |
= 28, 48, 56. |
Euphorbia hyssopifolia |
Euphorbia acuta |
|
Phenology | Flowering and fruiting late spring–early fall. | Flowering and fruiting spring–fall. |
Habitat | Disturbed areas, ditches, gardens. | Desert scrub, grasslands, oak-juniper savannas, limestone, rocky, sandy, or clay soils. |
Elevation | 0–1500 m. (0–4900 ft.) | 400–1900 m. (1300–6200 ft.) |
Distribution |
AL; AZ; FL; GA; LA; MS; NM; SC; TX; UT; Mexico; Central America; South America; West Indies [Introduced in tropical Asia, Africa, Australia]
|
NM; TX; Mexico (Chihuahua, Coahuila) |
Discussion | Euphorbia hyssopifolia is native to the New World tropics and is probably also native to parts of the southern United States. However, at least some of the records from the flora area appear to be from adventive plants. (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. 272. | FNA vol. 12, p. 259. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce hyssopifolia, E. jonesii, E. stenomeres | Chamaesyce acuta, E. acuta var. stenophylla, E. georgei |
Name authority | Linnaeus: Syst. Nat. ed. 10, 2: 1048. (1759) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) — name proposed for conservation |
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