Chromosomal and flavonoid chemical confirmation of intergeneric hybridization between Tolmiea and Tellima (Saxifragaceae)

Abstract

Two putative intergeneric hybrids between Tolmiea menziesii and Tellima grandiflora were discovered in Oregon and Washington. These plants are morphologically intermediate in several floral features between the presumed parental taxa. Evidence from flavonoid chemistry and karyology support the contention that these plants are of intergeneric hybrid origin. Cytological studies demonstrated that the hybrid plant from Oregon has 2n = 14 and involves diploid (2n = 14) Tolmiea menziesii and Tellima grandiflora. The hybrid plant from Washington has 2n = 21 and has tetraploid T. menziesii (2n = 28) and diploid T. grandiflora as parents. Tolmiea menziesii and Tellima grandiflora have distinctive karyotypes and both hybrid plants were found to combine these chromosomal complements. The hybrids also combine the flavonoid constituents of Tolmiea and Tellima. In addition to exhibiting kaempferol, quercetin, and myricetin glycosides found in both species, the hybrid plants have kaempferol and quercetin glycoside gallates characteristic of Tellima grandiflora, and isorhamnetin glycosides found in Tolmiea menziesii.