Euphorbia cordifolia |
Euphorbia velleriflora |
|
---|---|---|
heartleaf sandmat |
Caliche sandmat |
|
Habit | Herbs, annual, with taproot. | Herbs, perennial, with strongly thickened and lignified rootstock. |
Stems | prostrate, occasionally mat-forming, 10–43 cm, glabrous. |
prostrate, usually mat-forming, terete to slightly flattened and winged, to 30 cm, villous to pilose. |
Leaves | opposite; stipules usually distinct, occasionally connate at base, filiform, 1–1.2(–2.8) mm, usually glabrous, rarely pilose; petiole 0.4–1 mm, usually glabrous; blade ovate to oblong, 4.4–12 × 2.6–7.6 mm, base asymmetric, cordate to rounded, margins entire, apex rounded to mucronulate, surfaces glabrous; only midvein conspicuous. |
opposite; stipules distinct or connate at base, 2-fid to laciniate into 2–5 linear to subulate divisions, 0.5–1(–2) mm, glabrous or villous; petiole 0.5–2 mm, villous; blade usually ovate to oblong, rarely suborbiculate, 5–13 × 4–8 mm, base asymmetric, hemicordate, margins serrulate, apex obtuse, surfaces villous; 3-veined from base, usually only midvein conspicuous. |
Involucre | campanulate, 1–1.3 × 1–1.3 mm, glabrous; glands 4, yellowish to pink, elliptic, 0.3–0.5 × 0.5–1 mm; appendages whitish to pink, sometimes drying red, elliptic to ovoid, 1.1–1.5 × 1.2–1.9 mm, distal margin entire, retuse, or erose. |
turbinate, 0.9–1.4 × 0.7–1.1 mm, villous; glands 4, pink, oblong to reniform, 0.1–0.2 × 0.3–0.4 mm; appendages white to pink, flabellate, ovate, or oblong, 0.3–0.5 × 0.4–0.7 mm, distal margin entire, crenulate, or erose, often puberulent-ciliate. |
Staminate flowers | 5–40. |
8–12. |
Pistillate flowers | ovary glabrous; styles 0.5–0.8 mm, 2-fid nearly entire length. |
ovary villous; styles 0.2–0.4(–0.5) mm, 2-fid 1/2 length. |
Capsules | ovoid, 2–3 mm diam., glabrous; columella 1.2–2.7 mm. |
broadly ovoid, 1.5–1.9 × 1.3–1.7 mm, villous (uniformly so, but most pronounced toward base and along keels); columella 1.2–1.4 mm. |
Seeds | gray or tan with dark brown mottling, ovoid, bluntly 3–4-angled in cross section, 1.8–2.1 × 1.2–1.4 mm, smooth to rugose. |
white to gray or pink, narrowly pyramidal-ovoid, 4-angled in cross section, 1.1–1.3 × 0.4–0.6 mm, rugulose with shallow depressions separated by inconspicuous transverse ridges. |
Cyathia | solitary at distal nodes; peduncle 0.9–3 mm. |
solitary at distal nodes or at nodes of leafy, congested, axillary branches; peduncle 1–1.5(–2.5) mm. |
Euphorbia cordifolia |
Euphorbia velleriflora |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting summer. |
Habitat | Xeric oak-pine scrub, pine-barrens, sand barrens, sandy stream banks. | Disturbed habitats, particularly roadsides, grasslands, live oak-thorn scrub. |
Elevation | 0–200 m. (0–700 ft.) | 50–80 m. (200–300 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; OK; SC; TX
|
TX; Mexico; Central America (Guatemala) [Introduced in North America] |
Discussion | Euphorbia cordifolia is easily identified by its cordate to rounded leaf base and distinctive filiform stipules. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia velleriflora is native and widespread from northern Mexico to Guatemala. The species is apparently a recent introduction in southern Texas (W. R. Carr and M. H. Mayfield 1993), as the first records are from the 1990s. It is also expected in southern Arizona due to the presence of collections made a few kilometers south of the border in the Mexican state of Sonora. Euphorbia velleriflora is very similar to E. stictospora, and the two are sometimes confused. The two can be readily distinguished on the basis of their styles: unbranched in E. stictospora and 2-fid in E. velleriflora. Also, the involucral gland appendages of E. velleriflora are ciliate with short hairs, whereas those of E. stictospora are glabrous. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 265. | FNA vol. 12, p. 292. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce cordifolia | Anisophyllum velleriflorum, Chamaesyce velleriflora |
Name authority | Elliott: Sketch. Bot. S. Carolina 2: 656. (1824) | (Klotzsch & Garcke) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 40. (1862) |
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