HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

(American Journal of Botany. 2009;96:1041-1049.) doi: 10.3732/ajb.0800333 © 2009 Botanical Society of America, Inc.

What's this?

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Der, J. P. Articles by Wolf, P. G. Search for Related Content PubMed Articles by Der, J. P. Articles by Wolf, P. G. Agricola Articles by Der, J. P. Articles by Wolf, P. G. Social Bookmarking                            What's this?

Global chloroplast phylogeny and biogeography of bracken (Pteridium; Dennstaedtiaceae)¹

² Department of Biology, Utah State University, 5305 Old Main Hill, Logan, Utah 84322 USA ³ National Herbarium of New South Wales, Botanic Gardens Trust, Mrs Macquaries Road, Sydney, NSW 2000, Australia

ABSTRACT

Bracken ferns (genus Pteridium) represent an ancient species complex with a natural worldwide distribution. Pteridium has historically been treated as comprising a single species, but recent treatments have recognized several related species. Phenotypic plasticity, geographically structured morphological variation, and geographically biased sampling have all contributed to taxonomic confusion in the genus. We sampled bracken specimens worldwide and used variable regions of the chloroplast genome to investigate phylogeography and reticulate evolution within the genus. Our results distinguish two major clades within Pteridium, a primarily northern hemisphere Laurasian/African clade, which includes all taxa currently assigned to P. aquilinum, and a primarily southern hemisphere Austral/South American clade, which includes P. esculentum and P. arachnoideum. All European accessions of P. aquilinum subsp. aquilinum appear in a monophyletic group and are nested within a clade containing the African P. aquilinum taxa (P. aquilinum subsp. capense and P. aquilinum subsp. centrali-africanum). Our results allow us to hypothesize the maternal progenitors of two allotetraploid bracken species, P. caudatum and P. semihastatum. We also discuss the biogeography of bracken in the context of the chloroplast phylogeny. Our study is one of the first to take a worldwide perspective in addressing variation in a broadly distributed species complex.

Key Words: allopolyploidy • Dennstaedtiaceae • fern • hybridization • phylogeography • population • Pteridium • worldwide

Received for publication 1 October 2008. Accepted for publication 8 January 2009.

FOOTNOTES

¹ The authors thank many colleagues for material used in this study (see Appendix). Access to specimens collected by E. A. Ershova, V. V. Korzhenevsky, N. I. Shorina, and A. I. Shmakov for a collaborative taxonomic study of European brackens, a work still in progress, is also gratefully acknowledged. This research was funded in part by National Science Foundation grant DEB-0228432 to P.G.W. Computer time from the Center for High Performance Computing at Utah State University is acknowledged. The computational resource, the Uinta cluster supercomputer, was provided through the National Science Foundation under Grant No. CTS-0321170 with matching funds provided by Utah State University. A. R. Smith and K. M. Watrous provided useful comments on the manuscript.

⁴ Author for correspondence (e-mail: jpder{at}biology.usu.edu)

⁵ Present address: Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill, 450 West Drive, CB# 7295, Chapel Hill, NC 27599-7295 USA

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?