Euphorbia subilsieae (Euphorbiaceae), a new species from Argentina

A new species of Euphorbia that has been historically treated as E. dentata in Argentina is described and illustrated. The new species, Euphorbia subilsiae, is morphologicall similar to E. pentadactyla, the only other native species of the “Euphorbia dentata alliance” in Argentina, but it has bifid styles and less brightly colored umbel bracts. Euphorbia davidii, long thought to be native in Córdoba Province, should be considered as recently introduced in Argentina. It is now a common weed across Buenos Aires Province but is apparently less common further north in the country. A discussion of the distinctions among these species and their taxonomic history in Argentina is presented.