A compilation was made of 307 studies using nuclear DNA markers for evaluating among‐
and within‐population diversity in wild angiosperms and gymnosperms. Estimates derived …

Assessing the relative importance of the various pathways to diversification is a central goal
of biodiversity researchers. For plant biologists, and increasingly across the spectrum of …

The recurrent origin of diploid hybrid species is theoretically improbable because of the
enormous diversity of hybrid genotypes generated by recombination. Recent greenhouse …

Barriers to gene flow between species result from selection against foreign linkage blocks in
hybrids. When the geographic ranges of taxa meet at multiple locations, the opportunity …

Heiser (1949) hypothesized that a weedy race of Helianthus bolanderi had originated by the
introgression of genes from H. annum into a serpentine race of H. bolanderi. Although …

The sexual transfer of genes between taxa possessing different structural karyotypes must
involve the passage of genes through a chromosomal sterility barrier. Yet little is known …

Starting almost three decades ago, many scientists began to feel a degree of disillusionment
with the concepts of biosystematics (Raven, 1974; 1977b), a field then about twenty years …

• Premise of the study: Phylogenetic incongruence between “gene trees” and “species trees”
has been widely acknowledged in phylogenetic research. Conflicts may emerge from …

The internal transcribed spacer (ITS) region of 18S-26S nuclear ribosomal DNA (nrDNA)
has proven to be a useful source of characters for phylogenetic studies in many angiosperm …

Although there are many studies of the evolution and ecology of hybrid zones, few extend
over long enough time periods to track evolutionary changes in the zones or assess the …