Cytotaxonomy of Some Australian Species of Hibiscus Sect. Furcaria

Abstract

Chromosome numbers (2n= 108) and pairing are reported for eight species of the Australian alliance of Hibiscus sect. Furcaria. All are allohexaploids, the only natural hexaploids known in the section. Hybrids were obtained of H. heterophyllus with H. splendens, H. spinulosus, H. byrnesii, H. arnhemensis and H. menzeliae, and of H. splendens with H. spinulosus. Chromosome pairing was variable in the hybrids, but approached complete pairing in some samples of all combinations except H. splendens-spinulosus. Morphological and cytological similarities, geographical contiguity, and case of hybridization suggest that the species are closely related despite meiotic aberrations in some of the hybrids.