Euphorbia esula

Euphorbia esula-group. This species complex requires further study. One taxon, Euphorbia esula L. s.str., is probably native in Belgium, at least in the valley of river Meuse (Durand 1899). At present a narrow-leaved taxon is more frequent and doubtlessly non-native. It is usually referred to as Euphorbia esula subsp. tommasiniana (Bertol.) Kuzmanov (syn.: E. waldsteinii (Soják) Radcl.-Sm., E. virgata Waldst. & Kit., E. virgultosa Klokov) (Lambinon & Verloove 2012). However, the exact identity of the latter is uncertain. According to some sources these plants, at least in part, belong to a different taxon, possibly of hybrid origin: Euphorbia xpseudovirgata (Schur) Soó (syn.: E. esula subsp. pseudovirgata (Schur) Govaerts) (Stace 2010). Moreover, the correct name to apply is also uncertain. Recent German taxonomists (following Russian ones, mainly Geltman 1996) tend to adopt a narrow species concept. According to these authors names here accepted as synonyms of subsp. tommasiniana (and several others) represent distinct species. Our widespread plant then seems to belong to Euphorbia virgultosa Klokov, for which the correct name appears to be E. saratoi Ardoino (Reichert & al. 2018). A very useful and thoroughly illustrated account with notes on identification, nomenclature and taxonomy of this species complex is provided by the Euphorbia esula Arbeitsgruppe, see:

Selected literature:

Baiges J.C. & Blanche C. (1991) Morphologie des graines des espèces ibéro-baléariques du genre Euphorbia L. (Euphorbiaceae), 2. Subgen. Esula Pers. Bull. Soc. Bot. France, Lett. Bot. 138(4/5): 321-327.

Best K.F, Bowes G.G., Thomas A.G. & Maw M.G. (1980) The biology of Canadian weeds: 39. Euphorbia esula L. Canad. J. Pl. Sci. 60(2): 651-663.

Crompton C.W., Stahevitch A.E. & Wojtas W.A. (1990) Morphometric studies of the Euphorbia esula group in North America. Canadian Journal of Botany 68:1978-1988. [available online at:]

Durand T. (1899) Phanérogames. In: De Wildeman E. & Durand T., Prodrome de la flore belge. A. Castaigne Editeur, Bruxelles: 1112 p.

Geltman D.V. (1996) Taxonomic notes on species of subsection Esulae of the genus Euphorbia (Euphorbiaceae) from eastern Europe. Bot. Zhurn. 81: 73-89. (in Russian)

Geltman D.V. (1998) Taxonomic notes on Euphorbia esula (Euphorbiaceae) with special reference to its occurrence in the east part of the Baltic region. Ann. Bot. Fenn. 35: 113-117. [available online at:]

Geltman D.V. (2007) Conspectus of the system of Euphorbia L. subgenus Esula Pers. (Euphorbiaceae) of the nontropical Eurasia. Novosti Sist. Vyssh. Rast. 39: 224-240. (in Russian)

Henker H. (2010) Kritische Euphorbia-Sippen in der Sektion Esula in Mecklenburg-Vorpommern. Botanischer Rundbrief für Mecklenburg-Vorpommern 46: 3-25.

Juan R. & Pastor J. (1995) Contribucíon al estudio cariológico del género Euphorbia L. subgen. Esula Pers. Bol. Soc. Brot. Sér. 2 66: 41-54.

Kuzmanov B. (1964) On the origin of Euphorbia subg. Esula in Europe (Euphorbiaceae). Blumea 12: 369-379.

Lambinon J. & Verloove F. (avec coll. Delvosalle L., Toussaint B., Geerinck D., Hoste I., Van Rossum F., Cornier B., Schumacker R., Vanderpoorten A. & Vannerom H.) (2012) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Sixième édition. Jardin botanique national de Belgique, Meise: CXXXIX + 1195 p.

Molero J. & Rovira A. (1992) Euphorbia L. subsect. Esula (Boiss. in DC.) Pax in the Iberian peninsula. Leaf surface, chromosome number and taxonomic treatment. Collect. Bot. (Barcelona) 21: 121-181. [available online at:]

Radcliffe-Smith A. (1985) Taxonomy of North American leafy spurge. In: Watson A.K. (ed.), Leafy Spurge, Monograph series of the Weed Science Society of America. Chapter 3(3): 14-25. [available online at:]

Reichert H., Gregor T. & Meierott L. (2018) Euphorbia saratoi (= E. podperae, E. pseudovirgata auct., E. virgata var. orientalis, E. virgultosa) - in Mitteleuropa und Nordamerika ein Neophyt unklarer Herkunft. Kochia 11: 1-36. [available online at:

Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith