The Sorbus latifolia aggregate includes a group of mostly apomictic taxa thought to result from hybridization between S. torminalis and members of the S. aria aggregate. Some of these taxa are widespread, but others are local endemics, occuring in 'diversity hotspots', including the Wye Valley and the Avon Gorge in the UK. Nearly all of these endemics are extremely rare and protected by national legislation. Amplified fragment length polymorphism (AFLP) fingerprints demonstrate clear additivity in the S. latifolia aggregate between 'aria' and 'torminalis' fingerprints. One member of the S. aria aggregate, S. rupicola, has been suggested to be a parent of some members of the S. latifolia aggregate, although it can itself be diploid, triploid, or tetraploid and thought to result from hybridization between S. aria and another species, so far unidentified. On the basis of AFLP, we have been able to exclude S. rupicola in one case. Plastid DNA sequences for the trnL intron and the trnL-trnF intergenic spacer for members of the S. latifolia aggregate tested so far match the sequence for S. torminalis, indicating that for these samples, at least, the direction of hybridization is the same, with S. torminalis being the plastid donor (presumably female) parent.

Key words: AFLP, apomixis, hybridization, plastid DNA, Sorbus