The wild Pear is in no-doubt an archaeophyte in Britain. The three species of wild Pear we have in Britain:
Pear Pyrus communis L. - Fruit <(5)6cm, soft and sweet when mature, usually pear-shaped; non-spiny tree.
Wild pear Pyrus pyraster L. - Fruit <1.5-5cm, hardish when mature, round (apple-shaped); quite spiny tree.
Plymouth pear Pyrus cordata Desv. - Fruit <1.5(2)cm, hard and sour when mature, round (apple-shaped); very spiny, bushy tree.
All are frequently regarded as native, but more often P. communis is regarded as a wild, naturalised, denizen. Of the three species, I would say (speaking as a field botanist) that all three are non-native introductions, with the most recent arrival being P. communis, which may have arrived as late as the 11th century Normans. Pyrus pyraster has certainly been here for longer, as this occasionally turns-up in hedgerows far removed from domestic habitation and well away from public highways, and this was probably introduced during Roman times. None of the three species are in any way common, but the rarest, and the only British tree on the Red-list, schedule 8 protected tree species is that of the Plymouth pear Pyrus cordata Desv., for which we are the only nursery licenced to grow it for its species recovery program in Devon & Cornwall.
