Euphorbia bicolor

Engelmann & A. Gray

Boston J. Nat. Hist. 5: 233. 1845.

Common names: Snow-on-the-prairie
Endemic
Treatment appears in FNA Volume 12. Treatment on page 243. Mentioned on page 241.

Herbs, annual, with taproot. Stems erect, unbranched or branched, 40–100 cm, pilose. Leaves alternate; stipules 0.3–0.4 mm; petiole 0.3–1 mm, pilose; blade narrowly elliptic to lanceolate, 37–54 × 7–17 mm, base cuneate to slightly rounded, margins entire, apex aristate or acute, surfaces pilose; venation obscure, only midvein conspicuous. Cyathia in terminal pleiochasia dichasial and pleiochasial bracts linear to narrowly oblanceolate, with conspicuous white margins; peduncle 1.2–3 mm, densely pilose. Involucre campanulate, 2.7–3.5 × 2.2–3 mm, densely pilose; glands 4–5, green to pale greenish yellow, reniform, 0.6–0.7 × 1.4–1.6 mm; appendages white, obdeltate to orbiculate, 1.4–2.5 × 1.7–3 mm, dentate to erose. Staminate flowers 30–70. Pistillate flowers: ovary pilose; styles 0.7–1.2 mm, 2-fid 1/2 length. Capsules depressed-ovoid, 3.5–7.5 × 6–8.7 mm, densely pilose; columella 4.5–5.5 mm. Seeds tan to brown, ovoid, 4.3–4.5 × 3.7–3.9 mm, alveolate; caruncle absent.


Phenology: Flowering and fruiting summer–fall.
Habitat: Prairies, blackland (calcareous) prairies, pastures and clearings in former blackland prairie areas, roadside clearings.
Elevation: 100–200 m.

Discussion

Euphorbia bicolor is similar in appearance to E. marginata but can be distinguished by its linear to narrowly oblanceolate bracts and the presence of hairs on all parts of the plant.

Selected References

None.

Lower Taxa

None.

"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 bicolor"
acute;aristate +
0.14 cm1.4 mm <br />0.0014 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
obdeltate +  and orbiculate +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Jess A. Peirson +, Victor W. Steinmann +  and Jeffery J. Morawetz +
Engelmann & A. Gray +
cuneate +  and slightly rounded +
Alectoroctonum +
3.7 cm37 mm <br />0.037 m <br /> (5.4 cm54 mm <br />0.054 m <br />) +
narrowly elliptic;lanceolate +
0.7 cm7 mm <br />0.007 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
pleiochasial +
whorled +  and not opposite +
linear +  and narrowly oblanceolate +
cymose +, few-branched +  and unbranched +
additional +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.75 cm7.5 mm <br />0.0075 m <br />) +
depressed-ovoid +
0.6 cm6 mm <br />0.006 m <br /> (0.87 cm8.7 mm <br />0.0087 m <br />) +
exfoliating +
ceraceous +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
Snow-on-the-prairie +
Ark. +, La. +, Okla. +  and Tex. +
100–200 m. +
pistillate +  and staminate +
yellow +, green +  and pale greenish +
0.6mm;0.7mm +
subtending +
4 +  and 5 +
reniform +
1.4mm +  and 1.6mm +
Prairies, blackland (calcareous) prairies, pastures and clearings in former blackland prairie areas, roadside clearings. +
pleiochasial +  and dichasial +
axillary +  and terminal +
0.27 cm2.7 mm <br />0.0027 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
campanulate +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
caducous +, deciduous +  and persistent +
bractlike +
palmate +  and pinnate +
conspicuous +
crenulate +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
connate;distinct +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Flowering and fruiting summer–fall. +
opposite +  and whorled +
with white margins +  and green +
Boston J. Nat. Hist. +
0.43 cm4.3 mm <br />0.0043 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
alveolate +
0.37 cm3.7 mm <br />0.0037 m <br /> (0.39 cm3.9 mm <br />0.0039 m <br />) +
free +, connate +  and distinct +
branched +  and unbranched +
prostrate +  and decumbent +
40 cm400 mm <br />0.4 m <br /> (100 cm1,000 mm <br />1 m <br />) +
deciduous +  and persistent +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (?) +  and 0.12 cm1.2 mm <br />0.0012 m <br /> (?) +
Agaloma +  and Tithymalopsis +
Euphorbia bicolor +
Euphorbia sect. Alectoroctonum +
species +
in terminal monochasia +  and solitary +
10 +, 9 +, 8 +, 7 +  and 6 +