In the Southern Hemisphere there has been little phylogeographical investigation of forest refugia sites during the last glacial. Hooker's spleenwort, Asplenium hookerianum, is a fern that is found throughout New Zealand. It is strongly associated with forest and is a proxy for the survival of woody vegetation during the last glacial maximum. DNA sequence data from the chloroplast trnL-trnF locus were obtained from 242 samples, including c. 10 individuals from each of 21 focal populations. Most populations contained multiple, and in many cases unique, haplotypes, including those neighbouring formerly glaciated areas, while the predominant inference from nested clade analysis was restricted gene flow with isolation by distance. These results suggest that A. hookerianum survived the last glacial maximum in widespread populations of sufficient size to retain the observed phylogeography, and therefore that the sheltering woody vegetation must have been similarly abundant. This is consistent with palynological interpretations for the survival in New Zealand of thermophilous forest species at considerably smaller distances from the ice sheets than recorded for the Northern Hemisphere. Eastern and central North Island populations of A. hookerianum were characterized by a different subset of haplotypes to populations from the remainder of the country. A similar east-west phylogeographical pattern has been detected in a diverse array of taxa, and has previously been attributed to recurrent vulcanism in the central North Island.
b sequences of the chloroplast trnL-trnF intergenic spacer 21 of the 22 indigenous Asplenium taxa presently recognized f sequences of the chloroplast rbcL gene were also obtained from < representative of the diversity found in the trnL-trnF intergenic spacer. Phylogenetic analyses of these chloroplast sequence data indicate that the Asplenium species of New Zealand are not monophyletic. More specifically, the Asplenium species parti< ipating in hybridization in New Zealand form a closely related 'Austral' group, whereas the non-hybridizing species have closer sub-groups are recognized, represented by the species A. bulbiferum, A. flaccidum, and A. lineages in New Zealand, and the distributions of the many Asplenium species disjunct between New Zealand and elsewhere appear best explained by long-distance dispersal. The likely Asplenium, with approximately 700 species worldwide, appears to have a complex history of hybridization and auto-and allopolyploidy, and is a model group for the study of fern evolution (e.g.
The fern family Blechnaceae is cosmopolitan; however, the vast majority of species are placed in Blechnum, which occurs predominantly in the Southern Hemisphere. There are two areas that are particularly species–rich: the south–west Pacific (including Australasia), and Central and South America. Using chloroplast DNA sequences, we report the first comprehensive phylogenetic analysis of the Blechnaceae, including all genera widely recognised in recent treatments, and over half of the species. There is strong support for several major clades, which we characterise morphologically and geographically, and some of their interrelationships. Blechnum is confirmed as polyphyletic. Blechnum indicum and B. serrulatum are more closely related to Salpichlaena and Stenochlaena, and are segregated as a new genus, Telmatoblechnum. Alternative generic circumscriptions are discussed for the remainder of Blechnum. In the absence of morphological characters to diagnose the clades within core Blechnum, and for the sake of taxonomic stability, we advocate a broad circumscription for Blechnum. Brainea and Sadleria are retained as their relationships are not well resolved, but Doodia and Pteridoblechnum are clearly nested within the core of Blechnum and we provide four new names in Blechnum. Additionally, given the focus of our sampling, we discuss the biogeography of the south–west Pacific, where immigration has been more important in community assembly than what might be superficially inferred from patterns of endemism (with ca. 60% of species endemic to individual land areas).
A revised classification and checklist of New Zealand pteridophytes is presented, based on recently published phyletic schemes for the Pteridophyta, and on revisions of individual families and genera. The list comprises 211 species of which 22 are adventive and 189 native; the latter include 8 unnamed species (either undescribed or unidentified) and a further 6 which are subdivided into separate subspecies. Ofthe native taxa, 89 species (47%) and 3 subspecies (50%) are believed to be endemic to the New Zealand botanical region. Individual taxa are discussed with particular reference to recent revisions and areas requiring further study. Synonymic and alphabetical lists are provided of all validly published pteridophyte names based on New Zealand types or used by authors with reference to the New Zealand flora. The more important species erroneously or dubiously recorded for New Zealand are also listed.
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 two subspecies. The two allooctoploid lineages are accommodated under the reinstated name P. neozelandicum, each as a separate subspecies: P. neozelandicum subsp. neozelandicum and the new combination P. neozelandicum subsp. zerophyllum. The new combination P. wawranum is made for one of the tetraploid lineages, while the name P. oculatum is reinstated for the other. Polystichum richardii is a later synonym of P. neozelandicum, and hence is not a legitimate name for any of the taxa recognised here.
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