Patrick J. Brownsey

A community-derived classification for extant lycophytes and ferns

Phylogeny has long informed pteridophyte classification. As our ability to infer evolutionary trees has improved, classifications aimed at recognizing natural groups have become increasingly predictive and stable. Here, we provide a modern, comprehensive classification for lycophytes and ferns, down to the genus level, utilizing a community‐based approach. We use monophyly as the primary criterion for the recognition of taxa, but also aim to preserve existing taxa and circumscriptions that are both widely accepted and consistent with our understanding of pteridophyte phylogeny. In total, this classification treats an estimated 11 916 species in 337 genera, 51 families, 14 orders, and two classes. This classification is not intended as the final word on lycophyte and fern taxonomy, but rather a summary statement of current hypotheses, derived from the best available data and shaped by those most familiar with the plants in question. We hope that it will serve as a resource for those wanting references to the recent literature on pteridophyte phylogeny and classification, a framework for guiding future investigations, and a stimulus to further discourse.

A revised classification of New Zealand pteridophytes with a synonymic checklist of species

Abstract 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.

Fire and ice: volcanic and glacial impacts on the phylogeography of the New Zealand forest fern Asplenium hookerianum

In the Southern Hemisphere there has been little phylogeographical investigation of forest refugia sites during the last glacial. Hookers 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.

Insights into the Biogeography and Polyploid Evolution of New Zealand Asplenium from Chloroplast DNA Sequence Data

Abstract Nucleotide sequences of the chloroplast trnL-trnF intergenic spacer were obtained for 21 of the 22 indigenous Asplenium taxa presently recognized from New Zealand. Nucleotide sequences of the chloroplast rbcL gene were also obtained from eleven New Zealand species 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 participating in hybridization in New Zealand form a closely related ‘Austral’ group, whereas the non-hybridizing species have closer affinities to species from outside New Zealand. Within the Austral group, three well-supported sub-groups are recognized, represented by the species A. bulbiferum, A. flaccidum, and A. obtusatum. Dating analyses reject an 80 million year old vicariant origin for any of the Asplenium 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 chloroplast/maternal parent for each of the New Zealand octoploid species is discussed.

Checklist of dicotyledons, gymnosperms, and pteridophytes naturalised or casual in New Zealand: Additional records 1997–1998

Abstract New records of fully naturalised and casual plants are reported for the flora of New Zealand during the 3‐year period 2001–2003. Ten species are reported as additional or newly substantiated fully naturalised, 92 taxa are considered to be new records of casual plants, and 13 additional species that were previously known from few collections are given extended distributions.

New Zealand's pteridophyte flora—Plants of ancient lineage but recent arrival?

A hypothesis is presented that most pteridophytes arrived in New Zealand relatively recently, by long-distance dispersal. The flora comprises 194 native species, of which 89 (46%) are endemic and 105 (54%) are widespread. Of the latter, 90% are shared with temperate Australasia, 53% with tropical regions, 14% with temperate southern Africa and 13% with the circum-Antarctic islands and South America. New Zealand has undergone such dramatic changes in location, land area, and topography since initial separation from Gondwana 85 Ma that it seems improbable that the 95 species shared with temperate Australasia could have remained conspecific throughout that time. Modern fossil and molecular evidence strongly suggest that many families of ferns had not even evolved prior to separation, and palynological evidence from New Zealand indicates that 78% of pteridophyte genera first appeared there only after separation from Gondwana. Present-day distributions in New Zealand suggest that ferns have greater dispersal potential than flowering plants, and that pteridophyte distributions are more heavily influenced by temperature, rainfall, and geothermal activity than by geological history. Most endemic pteridophyte species have a predominantly southern distribution pattern and are characteristic of cool, lowland to montane forest. Pteridophytes in the northern part of New Zealand show a lower level of endemism than elsewhere and tend to be widespread species that have arrived from temperate Australasian and tropical regions. There is also evidence that at least some pteridophytes have migrated from New Zealand to Australia. It is suggested that the hypothesis of long-distance dispersal of pteridophytes across the Tasman Sea could be tested by molecular techniques.

Low-copy nuclear DNA sequences reveal a predominance of allopolyploids in a New Zealand Asplenium fern complex

Recent generalisations about polyploidy in plants have been largely based on studies of angiosperms. A compelling group to compare with angiosperms is ferns, because of their high polyploidy. The bi-parental inheritance of nuclear DNA sequence markers makes them advantageous for investigating polyploid complexes, but few such markers have been available for ferns. We have used DNA sequences from the low-copy nuclear LFY locus to study an Asplenium polyploid complex. The New Zealand species of this Austral group comprise seven tetraploids and eight octoploids. LFY sequences indicate that allopolyploidy is much more predominant than previously thought, being implicated in the origins of seven of the octoploids. One of the tetraploids has had a central role, being a progenitor for five of the octoploids. All of the octoploids appear to have relatively recent origins, with the dynamic environmental conditions of the Pleistocene possibly playing a role in their formation and/or establishment.

Parallel polyploid speciation: distinct sympatric gene‐pools of recurrently derived allo‐octoploid Asplenium ferns

Although polyploidy is widespread, its significance to the generation of biodiversity remains unclear. Many polyploids have been derived recurrently. For a particular polyploid, gene‐flow between the products of independent origin is typical where they come into contact. Here, we use AFLP DNA‐fingerprinting and chloroplast DNA sequences to demonstrate parallel polyploid speciation within both of the ferns Asplenium cimmeriorum and A. gracillimum. Both of these taxa comprise at least two allopolyploids, recurrently derived from the same progenitor pair. Each of these allopolyploids remain genetically distinguishable even with extensive sympatry, and could therefore be considered distinct species. To our knowledge, parallel speciation on this scale amongst recurrent polyploids has not been previously reported. With their parallel origins, these ‘evolutionary replicates’ provide an unrivalled opportunity to investigate how the reproductive barriers and ecological differentiation necessary for speciation arise following polyploidy.

A taxonomic revision of the New Zealand species of Hypolepis

Abstract Seven species of the fern genus Hypolepis Bernh. (Hypolepidaceae.: Dennstaedtiales) are recognised in New Zealand, including two, H. lactea and H. subantarctica, described for the first time and one new combination, H. ambigua. Three widely misapplied names, H. tenuifolia, H. punctata, and H. rugosula, are excluded from the New Zealand flora and the correct application of the names clarified. Six hybrid combinations are recorded, of which only one, H. ambigua × rufobarbata is common and all except H. lactea × rufobarbata are probably sterile. Hypolepis distans with n = 28 is cytologically and morphologIcally distinct from the other species and is thought to be representative of the primitive element 10 the genus. The other six species have. chromosome numbers of n = 52 or 104. Analysis of chromosomal pairing in wild hybrids suggests that the parent species have evolved by processes of autoand allopolyploidy similar to those demonstrated in many other genera of ferns.

A molecular phylogeny for the New Zealand Blechnaceae ferns from analyses of chloroplast trnL‐trnF DNA sequences

Abstract The Blechnaceae is one of the most speciose fern families in New Zealand, with two genera represented: Blechnum and Doodia. We se‐quenced the chloroplast trnL‐trnF locus for all of the Blechnaceae species indigenous to New Zealand, plus several non‐indigenous species. Although deeper relationships were not well resolved by phylogenetic analyses of these DNA sequences, several groupings of species were consistently recovered. Some of these relationships have been previously suspected on the basis of morphological similarity and/or hybridisation (e.g., the B. procerum group), and are consistent with variation in base chromosome numbers, but others were unexpected (e.g., the relationship of B. fluviatile and B. vulcanicum). The species of Doodia sampled here were found to be monophyletic, and were nested within a paraphyletic Blechnum. Infraspecific variation in the trnL‐trnF locus was detected within six New Zealand species, and may prove useful for future phylogeographic and taxonomic studies.