El complex <i>Euphorbia esula-E. virgata</i> (Euphorbiaceae) al nord-est de la península Ibèrica: precisions corològiques, ecològiques i taxonòmiques

Abstract

The recent discovery in the north-east of the Iberian Peninsula (southern and central Catalonia) of three populations belonging to the Euphorbia esula–E. virgata complex (Euphorbiaceae) prompted us to conduct a macro- and micromorphological study to ascertain their taxonomic identity. Only two previous records of plants from this complex existed in the area and these were gathered in 1908/1909 (previously identified as E. esula subsp. saratoi ) and in 1930 ( E. esula s. l. ). Our results indicate that all the material examined (both recent and old samples) can be attributed to E. virgata , a taxon whose main distribution area lies in eastern Europe, and whose southwestern distribution limit lies in northeastern Iberian Peninsula. The macromorphological characteristics vary somewhat between populations and some individual plants bear a strong resemblance to forms that are usually referred to E. ×pseudovirgata , a supposed hybrid of E. virgata and E. esula . It is not possible, however, to confirm the presence of this hybrid in the region without further studies. After this study, E. esula subsp. esula should be excluded from Catalonia, Valencia and Aragon. The present-day populations we attribute to E. virgata are highly localized but dense. They are found in herbaceous habitats with clear anthropic influence (abandoned fields and the edges of roads and tracks), on deep, fairly dry soils. These habitats are similar to those typical of E. virgata in eastern and central Europe. It is likely that the populations are temporal and indeed in two of the three recent localities it has been confirmed that they date from after 2005. Current data suggest that this is a non-indigenous species, but in view of the fact that it was detected a century ago, the possibility that it is a rare indigenous species with itinerant populations cannot be ruled out.