Flavonoid and xanthone patterns in bearded Iris species and the pathway of chemical evolution in the genus

Flavonoids, xanthones and isoflavones have been surveyed in leaf, flower and rhizome of four diploid and seven allopolyploid taxa of Bearded iris, in order to investigate their phylogeny. Eighteen glycoflavones and eight glucoxanthones were identified in the leaves and these compounds proved to be the most useful evolutionary markers. Both the diploid and allopolyploid taxa showed stable patterns, with minimal variation below the species level. The results showed that the species iris pseudopumila was a strong candidate as a diploid parent, while they ruled out the participation of iris pallida. Of the allopolyploids, I. germanica and I. albicans appeared to be very close, and I. biflora was also closely related possibly because of their supposed hybrid origin, cultivation and successive escapes from it. Iris marsica, which is endemic to the Abruzzi Region of Italy. has a distinct phenolic profile. Anthocyanin patterns in the flowers and isoflavone patterns in the rhizomes were generally uniform throughout the group. (C) 1997 Elsevier Science Ltd.