Euphorbia dentata |
Euphorbia conferta |
|
---|---|---|
green poinsettia, tooth poinsettia, tooth spurge |
Everglade key sandmat |
|
Habit | Herbs, annual, with taproot. | Herbs, annual, with taproot. |
Stems | erect or ascending, 15–60 cm, both pilose and inconspicuously strigillose; branches usually ± straight, occasionally proximal branches arcuate. |
prostrate, ascending, to erect, 10–45 cm, pilose. |
Leaves | usually opposite, occasionally alternate at distal nodes; petiole 5–20 mm, pilose; blade 30–70 × 4–35 mm, narrowly lanceolate to suborbiculate, usually broadest below middle, base usually acute to subobtuse, rarely subtruncate, margins coarsely crenate-dentate or doubly crenate, strigillose, flat to slightly revolute, apex broadly acute, abaxial surface long pilose with weak, filiform hairs, adaxial surface sparsely pilose to glabrate; venation pinnate, midvein prominent. |
opposite; stipules distinct, subulate, 1–2 mm, pilose; petiole 0.9–1.5 mm, pilose; blade oblanceolate to elliptic, 3–10 × 1–4 mm, base asymmetric, obtuse to hemicordate, margins coarsely serrate, sometimes revolute, apex rounded to acute, abaxial surface sparsely hispidulous to strigillose (densely so on young leaves), adaxial surface glabrous; 3-veined from base but only midvein conspicuous. |
Involucre | campanulate, 3.8 × 1.8 mm, glabrous; involucral lobes divided into several linear, smooth lobes; glands (1–)2, green, sessile and broadly attached, 0.7–0.9 × 0.9–1.2 mm, opening oblong, glabrous; appendages absent. |
campanulate, 1.1–1.4 × 0.5–0.7 mm, pilose; glands 4, red, narrowly reniform, 0.1 × 0.2–0.4 mm; appendages pink to red, larger 2 petal-like, smaller 2 elliptic, 0.4–1 × 0.3–0.5 mm, distal margin erose. |
Staminate flowers | 8–10. |
5–8. |
Pistillate flowers | ovary glabrous, styles 1.2 mm, 2-fid 1/2 to nearly entire length. |
ovary pilose; styles 0.4–0.8 mm, 2-fid at apex. |
Capsules | depressed-globose, 2.5–2.8 × 3.5–4 mm, 3-lobed, glabrous; columella 1.8–2.1 mm. |
conic or truncate-ovoid, 1–1.2 mm diam., pilose; columella 0.9–1.1 mm. |
Seeds | pale gray to black, ovoid, rounded in cross section, 2.1–2.7 × 1.7–2.1 mm, evenly minute-tuberculate; caruncle 0.4–0.6 mm. |
orange-brown, glaucous, oblong, 4-angled in cross section, 0.7–0.8 × 0.4–0.5 mm, slightly rugose and with 3–4 transverse ridges. |
Cyathial | arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched; pleiochasial bracts 2–4, often whorled, wholly green or paler green, white, or mauve at base, similar in shape and size to distal leaves or slightly narrower; dichasial bracts similar in shape to distal leaves but smaller (often highly reduced). |
|
Cyathia | peduncle 0.7–1 mm. |
solitary at distal nodes (appearing clustered at points of new growth); peduncle 0.4–0.6 mm. |
2n | = 28. |
|
Euphorbia dentata |
Euphorbia conferta |
|
Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting year-round. |
Habitat | Bottomland forests, stream and river banks, bluffs, prairies, glades, fallow fields, roadsides, railroad cinders, open disturbed areas. | Sandy, disturbed, wet areas, often roadsides. |
Elevation | 0–1000 m. (0–3300 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AL; AR; GA; IA; IL; IN; KS; KY; LA; MD; MI; MO; MS; NC; NE; OH; OK; PA; SC; TN; TX; VA; WV; ON; Mexico (Chihuahua, Coahuila, Nuevo León, Tamaulipas)
|
FL |
Discussion | Euphorbia dentata is native from northern Mexico and the south central United States north and east through the Ohio River Valley. Scattered occurrences in the southeastern United States likely represent adventive populations. Reports of E. dentata as a noxious weed (from the United States and the Old World) should most likely be attributed to introductions of E. davidii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia conferta is known only from Broward, Miami-Dade, and Monroe counties in southern Florida. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 321. | FNA vol. 12, p. 264. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Poinsettia dentata | Chamaesyce conferta |
Name authority | Michaux: Fl. Bor.-Amer. 2: 211. (1803) | (Small) B. E. Smith: J. Elisha Mitchell Sci. Soc. 62: 82. (1946) |
Web links |
|