Euphorbia davidii

Subils

Kurtziana 17: 125, figs. 1, 2H–J. 1984.

Common names: Toothed spurge
Treatment appears in FNA Volume 12. Treatment on page 320. Mentioned on page 318, 321.

Herbs, annual, with taproot. Stems erect or ascending, 20–70 cm, both coarsely and sparsely hirsute and closely strigillose; branches usually ± straight, occasionally proximal branches arcuate. Leaves usually opposite, occasionally alternate at distal nodes; petiole 7–25 mm, strigose; blade usually narrowly to broadly elliptic, occasionally lance-elliptic, 10–100 × 5–35 mm, base cuneate to attenuate, margins coarsely crenate-dentate, strigose, revolute to nearly flat, apex broadly acute to acuminate, or obtuse, abaxial surface strigose with stiff, strongly tapered hairs, adaxial surface sparsely strigose-hirsute; venation pinnate, midvein prominent. Cyathial arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched; pleiochasial bracts 2–4, often whorled, green with diffuse greenish white to mauve near 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 0.5–1 mm. Involucre cylindric, 2.5–3 × 1.3–1.8 mm, glabrous; involucral lobes divided into 5–7 linear, papillate lobes; gland 1, yellow-green, sessile and broadly attached, 0.9 × 1.3 mm, opening oblong, glabrous; appendages absent. Staminate flowers 5–8. Pistillate flowers: ovary glabrous or sparsely strigose; styles 1 mm, 2-fid 1/2 to nearly entire length. Capsules broadly ovoid, 2.9–3.3 × 4–4.8 mm, 3-lobed, glabrous; columella 2.2–2.7 mm. Seeds black to brown or pale gray, ovoid to triangular-ovoid, angular in cross-section, 2.4–2.9 × 2.2–2.9 mm, low-tuberculate, tubercles irregularly arranged or in faint, transverse row; caruncle 0.9–1.1 mm. 2n = 56.


Phenology: Flowering and fruiting summer–fall.
Habitat: Forests, stream and riverbanks, prairies, roadsides and open disturbed areas.
Elevation: 200–1500 m.

Distribution

V12 775-distribution-map.jpg

Ont., Que., Ariz., Ark., Calif., Colo., Fla., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Mass., Mich., Minn., Mo., Nebr., N.J., N.Mex., N.Y., N.C., Ohio, Okla., S.Dak., Tenn., Tex., Utah, Vt., Va., W.Va., Wis., Wyo., Mexico (Chihuahua), Mexico (Coahuila), Mexico (Sonora), in South America, Eurasia (China), Eurasia (Russia), Australia

Discussion

Euphorbia davidii is native from the southwestern United States and northern Mexico north through the southern Great Plains; it apparently is adventive elsewhere. The species is the weediest member of the E. dentata species group (following M. H. Mayfield 1997) and has become an agricultural weed in North America, South America (for example, Argentina), and in the Old World (particularly Australia and Russia). Euphorbia davidii can be distinguished from the closely similar E. dentata by its larger capsules and seeds, often more elliptic leaves, and shorter, stiffer hairs.

Selected References

None.

Lower Taxa

None.

"narrower" is not a number."connate" is not a number. "distinct" is not a number."/2" is not declared as a valid unit of measurement for this property.

... more about "Euphorbia davidii"
broadly acute;acuminate or obtuse +
Jess A. Peirson +, Paul E. Berry +  and Victor W. Steinmann +
Subils +
greenish white +  and mauve +
connate +
cuneate +  and attenuate +
Poinsettia +
lance-elliptic +  and elliptic +
1 cm10 mm <br />0.01 m <br /> (10 cm100 mm <br />0.1 m <br />) +
unlobed +
0.5 cm5 mm <br />0.005 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
dichasial +  and pleiochasial +
distinct +
2 +  and 4 +
reduced +
cymose +, few-branched +, unbranched +  and pleiochasial +
arranged +  and opposite +
additional +
0.29 cm2.9 mm <br />0.0029 m <br /> (0.33 cm3.3 mm <br />0.0033 m <br />) +
3-lobed +  and ovoid +
0.4 cm4 mm <br />0.004 m <br /> (0.48 cm4.8 mm <br />0.0048 m <br />) +
0.09 cm0.9 mm <br />9.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.27 cm2.7 mm <br />0.0027 m <br />) +
Toothed spurge +
Ont. +, Que. +, Ariz. +, Ark. +, Calif. +, Colo. +, Fla. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Mass. +, Mich. +, Minn. +, Mo. +, Nebr. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, Ohio +, Okla. +, S.Dak. +, Tenn. +, Tex. +, Utah +, Vt. +, Va. +, W.Va. +, Wis. +, Wyo. +, Mexico (Chihuahua) +, Mexico (Coahuila) +, Mexico (Sonora) +, in South America +, Eurasia (China) +, Eurasia (Russia) +  and Australia +
200–1500 m. +
pistillate +  and staminate +
yellow-green +
subtending +
Forests, stream and riverbanks, prairies, roadsides and open disturbed areas. +
tapered +
axillary +  and terminal +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
alternate +  and opposite +
caducous +, deciduous +  and persistent +
bractlike +
involucral +
papillate +
divided +
palmate +  and pinnate +
revolute +  and nearly flat +
strigose;glabrous +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
connate;distinct +
0.7 cm7 mm <br />0.007 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
Flowering and fruiting summer–fall. +
black;brown or pale gray +
0.24 cm2.4 mm <br />0.0024 m <br /> (0.29 cm2.9 mm <br />0.0029 m <br />) +
low-tuberculate +
ovoid +  and triangular-ovoid +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.29 cm2.9 mm <br />0.0029 m <br />) +
free +, connate +  and distinct +
ascending +  and erect +
strigillose +  and hirsute +
20 cm200 mm <br />0.2 m <br /> (70 cm700 mm <br />0.7 m <br />) +
deciduous +  and persistent +
distinct +
1 cm10 mm <br />0.01 m <br /> (?) +
hairy +  and glabrous +
Euphorbia davidii +
Euphorbia sect. Poinsettia +
species +
1-2-branched +  and pleiochasial +
in faint , transverse row +  and arranged +