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PremiseTheSphagnum recurvumcomplex comprises a group of closely related peat mosses that are dominant components of many northern wetland ecosystems. Taxonomic hypotheses for the group range from interpreting the whole complex as one polymorphic species to distinguishing 6–10 species. The complex occurs throughout the Northern Hemisphere, and some of the putative species have intercontinental ranges. Our goals were to delimit the complex and assess its phylogenetic structure in relation to morphologically defined species and intercontinental geography. MethodsRADseq analyses were applied to a sample of 384 collections from Europe, North America, and Asia. The data were subjected to maximum likelihood phylogenetic analyses and analyses of genetic structure using the software STRUCTURE and multivariate ordination approaches. ResultsTheS. recurvumcomplex includesS. angustifolium,S. fallax,S. flexuosum,S. pacificum, andS. recurvumas clades with little evidence of admixture. We also resolved an unnamed clade that is referred to here asS. “pseudopacificum.” We confirm thatS. balticumandS. obtusumare nested within the complex. Species with bluntly acute to obtuse stem leaf apices are sister to those with acute to apiculate leaves. Most of the species exhibit some differentiation between intraspecific population systems disjunct on different continents. ConclusionsWe recognize seven species in the amendedS. recurvumcomplex, includingS. balticumandS. obtusum, in addition to the informal cladeS. “pseudopacificum.” Although we detected some geographically correlated phylogenetic structure within widespread morphospecies, our RADseq data support the interpretation that these species have intercontinental geographic ranges.
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A phylogenomic analysis of Lonicera and its bearing on the evolution of organ fusion
Abstract PremiseThe ~140 species ofLoniceraare characterized by variously fused leaves, bracteoles, and ovaries, making it a model system for studying the evolution and development of organ fusion. However, previous phylogenetic analyses, based mainly on chloroplast DNA markers, have yielded uncertain and conflicting results. A well‐supported phylogeny ofLonicerawill allow us to trace the evolutionary history of organ fusion. MethodsWe inferred the phylogeny ofLonicerausing restriction site–associated DNA sequencing (RADSeq), sampling all major clades and 18 of the 23 subsections. This provided the basis for inferring the evolution of five fusion‐related traits. ResultsRADSeq data yielded a well‐resolved and well‐supported phylogeny. The two traditionally recognized subgenera (PericlymenumandChamaecerasus), three of the four sections (Isoxylosteum,Coeloxylosteum, andNintooa), and half of the subsections sampled were recovered as monophyletic. However, the large and heterogeneous sectionIsikawas strongly supported as paraphyletic.Nintooa, a clade of ~22 mostly vine‐forming species, includingL. japonica, was recovered in a novel position, raising the possibility of cytonuclear discordance. We document the parallel evolution of fused leaves, bracteoles, and ovaries, with rare reversals. Most strikingly, complete cupules, in which four fused bracteoles completely enclose two unfused ovaries, arose at least three times. Surprisingly, these appear to have evolved directly from ancestors with free bracteoles instead of partial cupules. ConclusionsWe provide the most comprehensive and well‐supported phylogeny ofLonicerato date. Our inference of multiple evolutionary shifts in organ fusion provides a solid foundation for in depth developmental and functional analyses.
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- Award ID(s):
- 1929670
- PAR ID:
- 10479657
- Publisher / Repository:
- American Journal of Botany
- Date Published:
- Journal Name:
- American Journal of Botany
- Volume:
- 110
- Issue:
- 4
- ISSN:
- 0002-9122
- Subject(s) / Keyword(s):
- ancestral character state reconstruction bracteoles classification cupule cytonuclear discordance fused ovaries honeysuckle parallel evolution phylogeny RADSeq
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/ajb2.16143
