Molecular confirmation of Potamogeton x bottnicus (P. pectinatus x P. vaginatus, Potamogetonaceae) in Britain

Restriction fragment length polymorphisms in the internal transcribed space r region of ribosomal DNA and in the chloroplast genome combine to confirm the existence of Potamogeton x bottnicus (P. pectinatus x P. vaginatus) in Britain. One of the parents, P. vaginatus, is not currently a member of the British nora, but did occur here in the past (the latest fossil fruits dat e from 30 000 BP) and the hybrid may therefore owe its origin to ancient po llination involving indigenous material or to more recent long-distance dis persal. (C) 2001 The Linnean Society of London.