Euphorbia albomarginata

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Rattlesnake Weed - Euphorbia albomarginata
Warm Springs Wash NE of Hillsboro New Mexico, USA
August 22, 2016

Following a walk we took on May 17, 2014, I noted that:  “Among the flowers that we saw were Rattlesnake Weed, Euphorbia albomarginata (formerly Chamaesyce a.), pictured at the top of this post and Ground Holly.  The “flower” of the Rattlesnake Weed is really a cup which has nectaries along its rim.  Inside the cup is one female flower surrounded by several male flowers - the male flower is simply a stamen, the female flower is one pistil on a short stem.”

It has a range which extends into northern Mexico, its range within the United States is shown in the BONAP map to the right - light green indicates that the species is native to, and not rare within, the county shown.

Among the other Common English names for this species is Whitemargin Sandmat.  In Spanish it is known as Golondrina (swallow) and Yerba de la vibora (viper grass).

This species had a number of uses in Native American Ethnobotany, including use as a salve for snakebites - thus, “Rattlesnake Weed”.  Note, however, that its sap is poisonous.  

The scientific synonyms for this species include Chamaesyce hartwegiana, Euphorbia hartwegiana, and Euphorbia stipulacea.  It was first described by John Torrey and Asa Gray.

The specimen shown below is another one of those collected as part of the US-Mexican Boundary Survey “under the direction of Major W. H. Emory, Commissioner, chiefly in the Valley of the Rio Grande, below Doñana - by C. C. Parry, M.D., J. M. Bigelow, M.D., Mr. Charles Wright, and Mr. A. Schott.” 


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© Robert Barnes 2018