Roadsides are frequently colonized by eurychorous species with a wide ecological and coenological amplitude. Stenoic and stenochorous plant species are often missing in synanthropic vegetation. An exception is Echium boissieri Steud., occurring in Central and Southern Spain, Portugal, Northern Morocco and Algeria. To determine whether this species is a “homeless roadside plant”, we analysed herbarium specimens, performed a detailed mapping of current populations on both sides of the Straits of Gibraltar, sampled phytosociological relevés and gathered the available coenological data from literature.
Echium boissieri is a hapaxanthous perennial herb and belongs to section Eleuterolepis. The analysis of herbarium specimens indicates a recent apophytization that implies a trend from primary (rocks, screes, landslides) and secondary habitats (extensive pastures, fallow lands) to roadsides during the last two centuries, particularly in Spain. This habitat change coincides with land‐use changes. The Chamaeleo gummiferi‐Echietum boissieri is described as a new association. This is a multi‐layered herbaceous vegetation type with an enormous species‐ and lifeform‐diversity. It is characterized by E. boissieri and Chamaeleon gummifer, and by the transgression of grassland (Phalaridetalia) and weed species (Ridolfion). The association grows on steep slopes of road embankments and on grazed pastures. The role of roadside habitats for nature conservation in intensively used landscapes is discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)