A Cryptic Invader of the Genus Persicaria (Polygonaceae) in La Palma and Gran Canaria (Spain, Canary Islands)

A cryptic invader of the genus Persicaria has recently increased in damper, northern parts La Palma and Gran Canaria Canary Islands (Spain) locally behaves as an invasive species. Examination historical herbarium specimens showed this species to be present since 1960s same probably applies Palma. Up now, had been assigned Old World weed P. maculosa. However, morphologically, these plants clearly correspond with hydropiperoides, a common widespread native New World, indeed morphologically similar Diagnostic features for two species, well another (P. decipiens, originally described from Islands), are compared, thoroughly discussed, copiously illustrated. The current distribution, ecology, naturalization status hydropiperoides also assessed. variability is more precisely taxonomic position southern ‘race’ it that sometimes referred distinct persicarioides, which Canarian belong. value latter appears clear, although at lower level. new combination, varietal rank, proposed validated. In addition our morphology-based study, molecular phylogenetic analysis conducted on nuclear ITS region plastid DNA trnL-F.