Reticulate evolution (resulting from interspeci?c hybridization) and hybrid genome duplication (allopolyploidy) have long been recognized as major processes generatingnew lineages frequentlyinvolved in biological invasion.The study is aimed to understand the genetics of inasvie species in genus Spartina (Poaceae). Interspeci?c hybridisation between the hexaploid Spartina alterni?ora (2n= 6x = 62, genomic composition AA) from North America and the native British hexaploid S. maritima (2n= 6x = 60, genomic composition MM) produced the largely infertile homoploid hybrid S. x townsendii (2n = 6x = 62, genomic composition AM), ?rst collected in 1870 at Hythe, Southampton, UK and named in 1880. The derived allopolyploid Spartina anglica C.E. Hubbard dodecaploid (2n = 12x = 120–124, genomic composition AAMM) is thought to have formed by spontaneous duplication of chromosome sets soon after the hybridisation even and spread world wide. Genome were sequenced at low coverage (0.5-2.0 x).