Intergeneric hybrids are generally rare; nevertheless, such putative hybrids need confirmation from other lines of evidence besides morphological intermediacy. In this study the authors used DNA sequences of nuclear and chloroplast genes to determine the hybrid identity of ×Chitalpa. Their results confirm that both ×Chitalpa tashkentensis `Pink Dawn' and ×C. tashkentensis `Morning Cloud' are the result of an Chilopsis linearis ×Catalpa sp. cross. However, Catalpa bignonioides does not seem to have participated in the cross, as speculated before. Different species of Catalpa may have been used as the paternal parent. ×C. tashkentensis `Morning Cloud' is the result of the C. linearis × C. speciosa cross, whereas the paternal parent of ×C. tashkentensis `Pink Dawn' may be a hybrid plant of C. ovata and C. speciosa.
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