Based upon a thin-layer chromatographic study of the phenolics of young leaves of the species of the genus Aegilops, in which affinities both within and among diploid and polyploid groups were compared, the following conclusions were drawn. No new compounds were found in the polyploid Aegilops species. A. ovata must have arisen from A. umbellulata and A. comosa. A. columnaris probably contains genetic material derived from members of the Sitopsis section. A. biuncialis contains parts of the genome of A. comosa and parts from some member of the Sitopsis section. A. variabilis contains an S or modified S genome. A. triuncialis contains the C and Cu genomes. A. cylindrica contains the genomes C and D. A. crassa(4x) has an S genome in its constitution. A. ventricosa seems to contain parts of the A. caudata genome. A. crassa (6x) contains one D genome, probably from A. squarrosa, one from A. bicornis, and the third genome appears to contain parts from the M and S genomes. A. juvenalis and A. triaristata (6x) contain a modified S genome.The present study supports the hypothesis that extensive natural hybridization and introgression has taken place during the evolution of the polyploid species.
Natural Hybridization and Introgression between Ligularia cymbulifera and L. tongolensis (Asteraceae, Senecioneae) in Four Different Locations