Euphorbia acuta
| Euphorbia acuta | |
|---|---|
| |
| Cyathium-type flower structure with immature fruit | |
| |
| Plant in habitat | |
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Malpighiales |
| Family: | Euphorbiaceae |
| Genus: | Euphorbia |
| Species: | E. acuta
|
| Binomial name | |
| Euphorbia acuta | |
| Synonyms | |
| |
Euphorbia acuta, the pointed sandmat, is a species of flowering plant.
Description
[edit]Pointed sandmat is an herbaceous plant with a strongly thickened rootstock enabling it to be a perennial. It stands erect, up to 30cm tall (~1 ft). Its leaves and stems are uniformly and densely covered with short to silky, white to gray hairs. Leaves, up to 20mm long and 8mm wide (~⅘ x 3/10 inch) are narrowly to broadly egg-shaped -- ovate to lanceolate.[2]
As with all Euphorbia species, the flowers of Euphorbia acuta are tiny and unisexual but arranged in a manner that clusters of male and female flower look like just one small blossom. Such structures are known as pseudanthia. Pseudanthia of the genus Euphorbia are of the special form known as cyathia. Each cyathium of Euphorbia acuta contains 20-25 male flowers consisting only of a single stamen; these surround the one stalked, female flower.[2] As the female flower's ovary enlarges, the stalk may grow longer so that the ovary hangs outside the cyathium, as it matures into a seed-bearing fruit.
Distribution
[edit]The native range of this species is the south-central USA and into the northern extreme parts of the northern Mexican states of Chihuahua and Coahuila
Habitat
[edit]In Texas, Euphorbia acuta is described as growing mainly on dry limestone uplands of the Edwards Plateau, and shrublands in the Semi-arid climate zone.[3]
Ecology
[edit]Fewer than 1% of green plant species are known to use the C2 photosynthetic pathway. Most plants use C3 or C4 photosynthesis. Euphorbia acuta uses C2 photosynthesis. It has been theorized that the C2 pathway enables the species using it to deal better with environmental stresses.[4]
Etymology
[edit]The genus name Euphorbia honors Euphorbus, a first-century A.D. Greek physician.[5]
The species name acuta is the Latin feminine form of acutus, meaning sharp-pointed.[6]
Taxonomy
[edit]In 1859 the taxon Euphorbia acuta Engelm. -- in 1836 there also had been an illegitimately published Euphorbia acuta Bellardi ex Colla from Eurasia -- was published in Volume 2, Part 1 of the "Report on the United States and Mexican boundary survey :made under the direction of the secretary of the Interior". The report was authored by the surveyor William H. Emory. During the surveying of the US/Mexico boundry, plants were collected, and the German-American botanist George Engelmann studied them. When a taxon was thought to be new to science, Engelmann published them, Latin descriptions and all. That's when Euphorbia acuta Engelm. came into being. In Engelmann's publication we read that the type specimen was found in "Stony prairies western Texas, along the San Pedro and Pecos rivers &c."[7]
References
[edit]- ^ "Euphorbia acuta Engelm". Plants of the World Online. Retrieved 22 July 2025.
- ^ a b Levin, Geoffrey A. (2016). "Euphorbia acuta". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 12. New York and Oxford: Oxford University Press. Retrieved 22 July 2025 – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
- ^ Sage, Tammy L.; Sage, Rowan F.; Vogan, Patrick; Ajeena, Bashar (March 31, 2011). "The occurrence of C2 photosynthesis in Euphorbia subgenus Chamaesyce (Euphorbiaceae)" (PDF). Journal of Experimental Botany. 62 (9). Toronto, Canada: Department of Ecology and Evolutionary Biology, The University of Toronto: 3183–95. doi:10.1093/jxb/err059.
- ^ Walsh, Catherine A.; Bräutigam, Andrea; Roberts, Michael R.; Lundgren, Marjorie r. (Nov 28, 2022). "Evolutionary implications of C2 photosynthesis: how complex biochemical trade-offs may limit C4 evolution". Journal of Experimental Botany. 74 (3). Oxford Journals: 707–722.
- ^ Berry, Paul E.; Riina, Ricarda; Peirson, Jess A.; Yang, Ya; Steinmann, Victor W.; Geltman, Dmitry V.; Morawetz, Jeffery J.; Cacho, Natalia. "EUPHORBIA Linnaeus". floranorthamerica.org. Flora of North America. Retrieved July 23, 2025.
- ^ "acuta". en-academic.com. Academic. Retrieved July 23, 2025.
- ^ Baird, Spencer Fullerton; Conrad, T. A.; Wendell, Cornelius; Emory, William H.; Smillie, James David; Englemann, George; Girard, Charles; Hall, James; Parry, C.C.; Michler, N.; Schott, Arthur; Torrey, John; States, United (1857). Report on the United States and Mexican boundary survey:made under the direction of the secretary of the Interior. Vol. 2. C. Wendell, printer.