Some plants of Polystichum from the Chatham Islands exhibit morphological character states unknown from the North and South Islands of New Zealand. Several workers have suggested that these plants should be given taxonomic recognition. However, analyses of morphological and molecular (AFLP‐DNA fingerprinting) data provide no strong evidence that these morphologically divergent Chatham Islands plants constitute an evolutionary...

Aim and location New Zealand began to separate from Gondwana c. 85 Ma, and has been isolated from the nearest large landmass, Australia, by some 2000 km of the Tasman Sea since c. 60 Ma. Given New Zealand's long geographical isolation, there has been considerable interest in explaining the origins of its different biotic elements. Here we investigate the biogeography of the fern genus Polystichum from temperate Australasia. Si...

Evidence is provided for the first demonstrated example of allopolyploidy in the New Zealand fern flora. Cytological, morphological, and molecular (AFLP‐DNA fingerprinting) analyses indicate that the fern previously known as Polystichum richardii constitutes an allopolyploid complex, in which four separate evolutionary lineages are present. These are here recognised as three taxonomic species, with one of these encompassing tw...