Genus Spartina (Chloridoideae,Poaceae) offers particular opportunities to investigate the consequences of hybridization and genome duplication (allopolyploidy) at different evolutionary time scales in natural populations.This genus exhibits various ploidy levels (from tetraploid to dodecaploid),and several examples of reticulate evolution with important ecological and evolutionary consequences,such as invasive hybrids or the recent formation of the salt marsh allopolyploid species Spartina anglica that displays larger ecological amplitude than its parental species and that has rapidly expanded in range (western Europe,America,China,Australia).