Euphorbia acuta

Engelmann in W. H. Emory

Rep. U.S. Mex. Bound. 2(1): 189. 1859.

Common names: Pointed sandmat
Synonyms: Chamaesyce acuta Millspaugh Euphorbia acuta var. stenophylla Boissier E. georgei Oudejans
Treatment appears in FNA Volume 12. Treatment on page 259. Mentioned on page 239, 251, 252, 254, 260.

Herbs, perennial, with strongly thickened rootstock. Stems ascending to erect, 5–30 cm, uniformly and densely canescent or sericeous. Leaves opposite; stipules deciduous, sometimes appearing absent, distinct, brown, linear-subulate, thin, 0.3–0.8 mm, canescent; petiole 0.4–1.2 mm, moderately to densely canescent; blade ovate to lanceolate, 6–20 × 3–8 mm, base subsymmetric, rounded to cuneate, margins entire, strongly involute, apex long-acuminate, spinulose, abaxial surface canescent to densely sericeous, adaxial surface glabrous or sparsely canescent; 3-veined from base but only midvein conspicuous. Cyathia solitary at distal nodes; peduncle 1.3–3.2 mm. Involucre turbinate to urceolate, 2–2.6 × 1.7–2.5 mm, villous to lanate; glands 4, yellow-green to orange or red, slightly concave, oblongelliptic, 0.2–0.4 × 0.6–1.5 mm; appendages white, flabellate, 1.1–2.1 × 0.2–0.6 mm, distal margin shallowly and irregularly toothed. Staminate flowers 20–25. Pistillate flowers: ovary strigose, pubescent to villous; styles 0.6–0.9 mm, 2-fid 1/2 length. Capsules subglobose to broadly ovoid, 2.8–3.7 mm diam., strigose, pubescent to villous; columella 2.3–3 mm. Seeds white, ovoid, 4-angled in cross-section, 2.2–2.6 × 1.1–1.4 mm, smooth to finely reticulate. 2n = 28, 48, 56.


Phenology: Flowering and fruiting spring–fall.
Habitat: Desert scrub, grasslands, oak-juniper savannas, limestone, rocky, sandy, or clay soils.
Elevation: 400–1900 m.

Distribution

V12 399-distribution-map.jpg

N.Mex., Tex., Mexico (Chihuahua), Mexico (Coahuila)

Discussion

Euphorbia acuta is easily distinguished in the field by its relatively large, strongly involute, hairy, and acutely pointed leaves. The name Euphorbia acuta Engelmann has been proposed for conservation against the earlier name E. acuta Bellardi ex Colla (P. E. Berry et al. 2011).

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 acuta"
56 +, 48 +  and 28 +
canescent +  and densely sericeous +
canescent +  and glabrous +
long-acuminate +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.21 cm2.1 mm <br />0.0021 m <br />) +
flabellate +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
Victor W. Steinmann +, Jeffery J. Morawetz +, Paul E. Berry +, Jess A. Peirson +  and Ya Yang +
Engelmann in W. H. Emory +
subsymmetric +
pinnate +, symmetric +  and asymmetric +
rounded +  and cuneate +
Anisophyllum +
0.6 cm6 mm <br />0.006 m <br /> (2 cm20 mm <br />0.02 m <br />) +
ovate;lanceolate +
0.3 cm3 mm <br />0.003 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
0.28 cm2.8 mm <br />0.0028 m <br /> (0.37 cm3.7 mm <br />0.0037 m <br />) +
pubescent +  and villous +
subglobose +  and broadly ovoid +
0.23 cm2.3 mm <br />0.0023 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Pointed sandmat +
N.Mex. +, Tex. +, Mexico (Chihuahua) +  and Mexico (Coahuila) +
400–1900 m. +
pistillate +  and staminate +
yellow-green +  and orange or red +
0.2mm;0.4mm +
subtending +
oblongelliptic +  and concave +
0.6mm +  and 1.5mm +
Desert scrub, grasslands, oak-juniper savannas, limestone, rocky, sandy, or clay soils. +
axillary +  and terminal +
0.2 cm2 mm <br />0.002 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
villous +  and lanate +
turbinate +  and urceolate +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
caducous +, deciduous +  and persistent +
bractlike +
palmate +  and pinnate +
toothed +  and entire +
pubescent;villous +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.32 cm3.2 mm <br />0.0032 m <br />) +
connate;distinct +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
Flowering and fruiting spring–fall. +
Rep. U.S. Mex. Bound. +
smooth;finely reticulate +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
4-angled +  and ovoid +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.14 cm1.4 mm <br />0.0014 m <br />) +
free +, connate +  and distinct +
ascending +  and erect +
sericeous +  and canescent +
flattened +  and terete +
5 cm50 mm <br />0.05 m <br /> (30 cm300 mm <br />0.3 m <br />) +
interpetiolar +
connate +  and distinct +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (?) +  and 0.09 cm0.9 mm <br />9.0e-4 m <br /> (?) +
hairy +  and glabrous +
Chamaesyce acuta +, Euphorbia acuta var. stenophylla +  and E. georgei +
Euphorbia acuta +
Euphorbia sect. Anisophyllum +
species +
axillary +  and terminal +
10 +, 9 +, 8 +, 7 +  and 6 +