Contribution to the knowledge of the alien flora in northern and central Catalonia (NE Iberian Peninsula)

We provide floristic data about some rare alien plants in Catalonia, mainly garden escapes. According to the available information, these species are reported for the first time in the Iberian Peninsula: Euphorbia glyptosperma Engelm. (naturalised), Clerodendrum bungei Steud., Clerodendrum trichotomum Thunb., Cotoneaster divaricatus Rehder & E. H. Wilson and Opuntia scheeri F.A.C. Weber (casuals). These species were previously reported
for the Iberian Peninsula but are new taxa for the Catalan flora: Helianthus × laetiflorus Pers. (naturalitsed), Achillea ptarmica L., Tradescantia pallida (Rose) D.R. Hunt and Tradescantia zebrina Bosse (casuals). We also confirm the presence of Atriplex tatarica L., a species sometimes considered doubtful for the Iberian flora.