| Abstract: | Of three computer-generated classifications of Pyrus species, produced respectively from 29 chemical characters, 22 botanical characters and all 51 characters taken together, the classification based upon both chemical and botanical characters agrees best with the known geographical distributions of the species. Where either chemical or botanical characters are separately employed, the classifications contain seriously misplaced species. The numerical classification based upon all 51 characters lends some support to the division of the genus into four principal groups of species: the East Asian pea pears, the larger-fruited East Asian pears, the North African pears and the European and West Asian pears. P. longipes, P. betulifolia and P. cordata are considered as being connecting links between the East Asian pea pears, the larger-fruited East Asian pears and the European and West Asian pears. Some speculations are made on the phylogenetic relationships among Pyrus species. |
