Evidence for an allopolyploid complex in New ZealandPolystichum(Dryopteridaceae)

Abstract

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.

Morphological and genetic diversity in the New Zealand fernPolystichum vestitum(Dryopteridaceae), with special reference to the Chatham Islands

“…Scatter-plots were used to assess which pairs of quantitative morphological characters exhibited concordant partitioning, where the samples are more or less restricted to two diagonally opposite quadrants of the graph. Perrie et al (2003a) considered that two independent characters were only likely to show concordant partitioning if two separate lineages, or assortatively fertilising groups of individuals, were present.…”

“…Following the approach of Perrie et al (2003a), we test the null hypothesis that P. vestitum sens. lat.…”

A review of genetic analyses of hybridisation in New Zealand

“…In some cases, octoploids share multiple chloroplast types with each other and their progenitors, indicating repeated polyploidisation events (A. gracillimum, A. cimmeriorum (Perrie & Brownsey 2005b)). Allopolyploidy in New Zealand ferns has also been documented using molecular approaches vnPolystichum, where P. neozelandicum is an allo-octoploid of the tetraploids P. wawranum and P. oculatum (Perrie et al 2003). Chloroplast sequences indicate that the tetraploid Hypolepis ambiguamay be composed of independently derived allopolyploid lineages of unknown parentage (Perrie & Brownsey unpubl.…”

“…gracillimum has inferred parents^, bulbiferum andA. hookerianum; Perrie & Brownsey 2005a;Shepherd et al 2008a); 2% P olystichum neozelandicum (inferred parentage P. wawranum and P. oculatum; Perrie et al 2003);…”

What We Do (and Don't) Know About Ferns: <I>Dryopteris</I> (Dryopteridaceae) as a Case Study

“…Both of these large genera include patterns of reticulate speciation that have been the focus of recent molecular studies, e.g. Schneider et al (2012), Dyer et al (2012), and Chang et al (2013) on Asplenium and Perrie et al (2003) on Polystichum. Schneider and colleagues' (2012) study of Asplenium using two low-copy nuclear markers plus ITS found conflict between the markers that they interpreted as evidence of ancient reticulation events.…”