A biosystematic study of a wild population of leptopteris hybrids in new zealand

Abstract

The results of a morphological and cytological investigation of a natural population of Leptopteris species and hybrids growing near Wellington are reported. Biometric analysis of 34 mature plants indicates that only representatives of L. hymenophylloides, L. superba, and their F1 hybrids are present. Regular bivalent formation at meiosis and the presence of well-formed spores in the F1 hybrids suggest some degree of fertility. Reasons for the apparent absence of F2 plants and back-cross hybrids are discussed. The occurrence of regular bivalent formation in the hybrid plants is unexpected but probably indicates that the chromosomes of L. hymenophylloides and L. superba have not diverged as rapidly as their morphological and ecological characteristics. It is suggested that the two Leptopteris species are only one of several imperfectly distinguished species pairs in the New Zealand fern flora which are still diverging after immigration into an island flora. L. hymenophylloides and L. superba are typified and their synonymies corrected. A new combination, L. x intermedia (André) Brownsey, is proposed for hybrids between the two species. © 1981 Taylor & Francis Group, LLC.