Cytological affinities of the Australasian species ofEpilobium(Onagraceae)

Abstract

Abstract In the genus Epilobium (Onagraceae) an examination ot meiosis in 41 experimental hybrids, involving 25 of the 46 native species of Australia. New Zealand. and New Guinea. as well as standard strains from North America and Europe has shown that all the Australasian species have the BB chromosome arrangement, widespread in the Old World. A single plant of E. microphyllum from Rainy River, Nelson, New Zealand, had a chromosome arrangement that diltered from BB by a single reciprocal translocation, but four other plants from the same area were BB; the deviant arrangement is designated B1B1 and appears to have originated in situ. Ubiquity of the BB chromosome arrangement in Australasia is consistent with the postulated origin of all native species after a single introduction from Asia during the past several million years.