Euphorbia spathulata

Lamarck in J. Lamarck et al.

Encycl. 2: 428. 1788.

Common names: Warty spurge
WeedyIllustrated
Synonyms: Euphorbia arkansana Engelmann & A. Gray E. dictyosperma Fischer & C. A. Meyer E. obtusata Pursh Galarhoeus arkansanus (Engelmann & A. Gray) Small ex Rydberg G. obtusatus (Pursh) Small ex Rydberg Tithymalus arkansanus (Engelmann & A. Gray) Klotzsch & Garcke T. dictyospermus (Fischer & C. A. Meyer) A. Heller T. obtusatus (Pursh) Klotzsch & Garcke T. spathulatus (Lamarck) W. A. Weber
Treatment appears in FNA Volume 12. Treatment on page 309. Mentioned on page 295, 298, 310, 311.

Herbs, usually annual, rarely biennial, with taproot. Stems erect or ascending, unbranched or branched, 10–70 cm, glabrous. Leaves: petiole absent or to 0.2 mm; blade oblanceolate, oblong-oblanceolate, spatulate, or cuneate, 10–50 × 6–11 mm, base broadly attenuate to rounded or shallowly cordate-clasping, margins finely serrulate (usually distally), apex usually rounded to obtuse, occasionally slightly retuse or obcordate proximally, bluntly mucronate, surfaces glabrous; venation pinnate, midvein prominent. Cyathial arrangement: terminal pleiochasial branches 3 (–5), each 1–3 times 2-branched; pleiochasial bracts broadly ovate to ovate-oblong, shorter and wider than distal leaves; dichasial bracts distinct, broadly ovate, ovate-triangular, or ovate-elliptic, base cordate-clasping or subcordate to rounded, margins serrulate, apex rounded to obtuse or acute; axillary cymose branches (0–4) 5–12. Cyathia: peduncle 0.3–1 (–1.5) mm. Involucre campanulate to cupulate, 0.6–1 (–1.5) × 0.8–1.2 mm, glabrous; glands 4–5, elliptic, oblong, to slightly reniform, 0.2–0.6 × 0.4–1 mm; horns absent. Staminate flowers 3–10. Pistillate flowers: ovary glabrous; styles 0.8–1.5 mm, 2-fid. Capsules depressed-globose, 2–3.5 × 4 mm, 3-lobed; cocci rounded, verrucose, verrucae 0.1–0.2 mm, glabrous; columella 1.4–2.2 mm. Seeds redbrown to dark purple, occasionally ± glaucous, broadly ellipsoid-ovoid to nearly globose, 1.3–2.5 × 1.5–1.8 mm, smooth, reticulate, or finely low-ridged; caruncle irregularly reniform to round, subconic to lenticular, 0.3–0.4 × 0.5–0.6 mm.


Phenology: Flowering and fruiting spring–summer.
Habitat: Forests, fallow fields, prairies, pastures, glades, stream banks, waste places, roadsides.
Elevation: 0–3500 m.

Distribution

V12 345-distribution-map.jpg

Ont., Ala., Ariz., Ark., Calif., Colo., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Md., Mich., Minn., Miss., Mo., Mont., Nebr., N.Mex., N.C., N.Dak., Ohio, Okla., Oreg., Pa., S.C., S.Dak., Tenn., Tex., Utah, Va., Wash., W.Va., Wis., Wyo., Mexico (Chihuahua), Mexico (Sonora), s South America

Discussion

As treated here, Euphorbia spathulata is a wide-ranging and variable species. J. B. S. Norton (1900) recognized a number of segregates (for example, E. arkansana, E. dictyosperma, and E. obtusata) all of which are included here in a broadly defined E. spathulata. The only segregate species that has been widely recognized in regional floras is E. obtusata (for example, M. L. Fernald 1950; T. S. Cooperrider 1995; G. Yatskievych 1999–2013, vol. 2). Authors have generally distinguished the eastern North American E. obtusata from the western E. spathulata by the former's larger seeds (1.7–2.3 mm versus 1.5–1.7 mm) with smooth (versus reticulate) surfaces, larger involucres, red (versus yellow) involucral glands, and cordate-clasping (versus rounded to subcordate) dichasial bracts. Examination of specimens of E. spathulata in the broad sense from throughout North America showed that there is some geographic patterning to seed size and surface sculpturing, but the variation does not segregate cleanly into two discrete taxa. Plants from western North America typically have small seeds (1.5–1.7 mm) with reticulate surfaces, although some western individuals have seeds 1.8–1.9 mm long with reticulate surfaces. Plants from Texas generally have small seeds (1.5–1.6 mm) but with the surfaces either reticulate or completely smooth. Plants from adjacent Louisiana have small seeds with faintly reticulate to almost bumpy surfaces. Plants from eastern North America have larger seeds (2–2.3 mm) with usually smooth surfaces, although individuals from Tennessee and the Carolinas have faintly reticulate surfaces. Involucre height, gland color, and the shape of the dichasial bracts do not segregate with seed size as previous treatments have suggested.

Selected References

None.

Lower Taxa

None.

"shorter and wider" is not a number."connate" is not a number. "distinct" is not a number."connate" is not a number. "distinct" is not a number.

... more about "Euphorbia spathulata"
rounded;obtuse or acute +
Ricarda Riina +, Dmitry V. Geltman +, Jess A. Peirson +  and Paul E. Berry +
Lamarck in J. Lamarck et al. +
subcordate to rounded +  and cordate-clasping +
unlobed +
dichasial +  and pleiochasial +
distinct +
ovate-elliptic +, ovate-triangular +, ovate +, broadly ovate +  and ovate-oblong +
cymose +, branched +, unbranched +  and pleiochasial +
arranged +  and opposite +
additional;2;4 +
0.2 cm2 mm <br />0.002 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
3-lobed +  and depressed-globose +
4 cm40 mm <br />0.04 m <br /> (?) +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
irregularly reniform +  and round subconic +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
verrucose +
rounded +
0.14 cm1.4 mm <br />0.0014 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
Warty spurge +
Ont. +, Ala. +, Ariz. +, Ark. +, Calif. +, Colo. +, D.C. +, Fla. +, Ga. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Md. +, Mich. +, Minn. +, Miss. +, Mo. +, Mont. +, Nebr. +, N.Mex. +, N.C. +, N.Dak. +, Ohio +, Okla. +, Oreg. +, Pa. +, S.C. +, S.Dak. +, Tenn. +, Tex. +, Utah +, Va. +, Wash. +, W.Va. +, Wis. +, Wyo. +, Mexico (Chihuahua) +, Mexico (Sonora) +  and s South America +
0–3500 m. +
pistillate +  and staminate +
0.2mm;0.6mm +
subtending +
4 +  and 5 +
oblong +  and slightly reniform +
0.4mm +  and 1mm +
Forests, fallow fields, prairies, pastures, glades, stream banks, waste places, roadsides. +
axillary +  and terminal +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
campanulate +  and cupulate +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
caducous +, deciduous +  and persistent +
bractlike +
palmate +  and pinnate +
toothed +  and entire +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
connate;distinct +
hairy +  and glabrous +
Flowering and fruiting spring–summer. +
redbrown;dark purple +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
low-ridged +, broadly ellipsoid-ovoid +  and nearly globose +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
Weedy +  and Illustrated +
free +, connate +  and distinct +
branched +  and unbranched +
ascending +  and erect +
10 cm100 mm <br />0.1 m <br /> (70 cm700 mm <br />0.7 m <br />) +
herbaceous +  and woody +
deciduous +  and persistent +
connate +  and distinct +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (?) +  and 0.15 cm1.5 mm <br />0.0015 m <br /> (?) +
hairy +  and glabrous +
Euphorbia arkansana +, E. dictyosperma +, E. obtusata +, Galarhoeus arkansanus +, G. obtusatus +, Tithymalus arkansanus +, T. dictyospermus +, T. obtusatus +  and T. spathulatus +
Euphorbia spathulata +
Euphorbia subg. Esula +
species +
1-3 times 2-branched +  and pleiochasial +
rounded +  and attenuate +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
biennial +  and annual +
10 +, 9 +, 8 +, 7 +  and 6 +