Once more unto the breach, dear friends: Resolving the origins and relationships of the Pellaea wrightiana hybrid complex.

Premise: The taxonomic status of Wright's cliff brake fern, Pellaea wrightiana, has been in dispute ever since it was first described by Hooker in 1858. Previously published evidence suggested that this "taxon" may represent a polyploid complex rather than a single discrete species, a hypothesis tested here using a multifaceted analytical approach.

Methods: Data derived from cytogenetics, spore analyses, leaf morphometrics, enzyme electrophoresis, and phylogenetic analyses of plastid and nuclear DNA sequences are used to elucidate the origin, relationships, and taxonomic circumscription of P.

Diversification and reticulation in the circumboreal fern genus Cryptogramma.

We investigated the evolutionary complexity that resulted from cryptic diversification and polyploidy in parsley ferns (Cryptogramma). A total of 14 species were included in our data set, with six outgroup species and eight Cryptogramma species. DNA sequence data from six plastid loci (rbcL, rbcL-accD, rbcL-atpB, rps4-trnS, trnG-trnR and trnP-petG) were analyzed using maximum likelihood and Bayesian methods to provide the first rigorous assessment of diversification in the genus, including testing the monophyly of the genus and sections.

Relation between stable isotope ratios in human red blood cells and hair: implications for using the nitrogen isotope ratio of hair as a biomarker of eicosapentaenoic acid and docosahexaenoic acid.

Background: The nitrogen isotope ratio (expressed as delta(15)N) of red blood cells (RBCs) is highly correlated with the RBC long-chain omega-3 (n-3) fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in Yup'ik Eskimos. Because delta(15)N can also be measured in hair samples, it could provide a noninvasive, retrospective biomarker for EPA and DHA intakes.

Objectives: We investigated the agreement between delta(15)N in hair and RBCs and then evaluated the relations between hair delta(15)N and RBC EPA and DHA.

A molecular phylogeny of scaly tree ferns (Cyatheaceae).

Tree ferns recently were identified as the closest sister group to the hyperdiverse clade of ferns, the polypods. Although most of the 600 species of tree ferns are arborescent, the group encompasses a wide range of morphological variability, from diminutive members to the giant scaly tree ferns, Cyatheaceae. This well-known family comprises most of the tree fern diversity (∼500 species) and is widespread in tropical, subtropical, and south temperate regions of the world.

Tree ferns: monophyletic groups and their relationships as revealed by four protein-coding plastid loci.

Tree ferns are a well-established clade within leptosporangiate ferns. Most of the 600 species (in seven families and 13 genera) are arborescent, but considerable morphological variability exists, spanning the giant scaly tree ferns (Cyatheaceae), the low, erect plants (Plagiogyriaceae), and the diminutive endemics of the Guayana Highlands (Hymenophyllopsidaceae). In this study, we investigate phylogenetic relationships within tree ferns based on analyses of four protein-coding, plastid loci (atpA, atpB, rbcL, and rps4).