Euphorbia cordifolia |
Euphorbia trichotoma |
|
---|---|---|
heartleaf sandmat |
sand-dune spurge |
|
Habit | Herbs, annual, with taproot. | Herbs, perennial, with thick rootstock. |
Stems | prostrate, occasionally mat-forming, 10–43 cm, glabrous. |
erect, branched, 15–40 cm, glabrous. |
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. |
petiole absent; blade obovate to oblanceolate, 5–20 × 2–7 mm, base broadly attenuate, margins entire, apex acute to obtuse, surfaces glabrous; venation pinnate, very obscure, midvein prominent. |
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. |
hemispheric, 1–1.5 × 1.4–2 mm, glabrous; glands 5, elliptic to slightly crescent-shaped, 0.4–0.6 × 0.9–1.1 mm; horns divergent, 0.1–0.2 mm. |
Staminate flowers | 5–40. |
8–10. |
Pistillate flowers | ovary glabrous; styles 0.5–0.8 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.2–0.4 mm, 2-fid. |
Capsules | ovoid, 2–3 mm diam., glabrous; columella 1.2–2.7 mm. |
depressed-ovoid, 1.1–1.5 × 2–3 mm, strongly 3-lobed; cocci rounded, minutely papillate, sometimes appearing smooth, glabrous; columella 1.6–1.9 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, ovoid-globose, 1.8–2 × 1.6–1.8 mm, smooth; caruncle ± rounded and flattened, 0.3 × 0.3 mm. |
Cyathia | solitary at distal nodes; peduncle 0.9–3 mm. |
peduncle 0.7–1 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3, each usually 1–2 times 3-branched, sometimes unbranched; pleiochasial bracts similar in shape and size to distal leaves, alternate; dichasial bracts distinct, obovate to oblanceolate, base broadly attenuate, margins entire, apex acute to obtuse; axillary cymose branches 0. |
|
Euphorbia cordifolia |
Euphorbia trichotoma |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting year-round (primarily spring–summer). |
Habitat | Xeric oak-pine scrub, pine-barrens, sand barrens, sandy stream banks. | Coastal beaches, sand dunes, thickets. |
Elevation | 0–200 m. (0–700 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; OK; SC; TX
|
FL; Mexico; Central America; West Indies |
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 trichotoma is found in coastal peninsular Florida from Hillsborough County south to Key West. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 265. | FNA vol. 12, p. 311. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Chamaesyce cordifolia | Galarhoeus trichotomus, Tithymalus trichotomus |
Name authority | Elliott: Sketch. Bot. S. Carolina 2: 656. (1824) | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 2(fol.): 48; 2(qto.): 60. (1817) |
Web links |