In the early 2000s, homeowners in Washington, DC’s leafy Spring Valley neighborhood received some unwelcome news. The Army Corps of Engineers had discovered that the soil on 177 of the Spring Valley properties contained unsafe levels of arsenic, a remnant of World War I-era weapons testing in the area (1). On highly contaminated properties, the Corps dug up yards and hauled soil away. On proper...

MatK, the only maturase gene in the land plant plastid genome, is a very popular phylogenetic marker that has been extensively applied in reconstructing angiosperm phylogeny. However, the use of matK in fern phylogeny is largely unknown, due to difficulties with amplification: ferns have lost the flanking trnK exons, typically the region used for designing stable priming sites. We developed pri...

Ferns (Pteridophyta) are very important members of the plant kingdom that lag behind other taxa with regards to our understanding of their genetics, genomics, andmolecular biology. We report here, to our knowledge, the first instance of stable transformation of fern with recovery of transgenic sporophytes. Spores of the arsenic hyperaccumulating fern Pteris vittata and tetraploid ‘C-fern Expres...

Across the tree of life, molecular phylogenetic studies often reveal surprising relationships between taxa with radically different morphologies that have long obscured their close affiliations. A spectacular botanical example is Rafflesia, a holoparasite that produces the largest flowers in the world, but that evolved from tiny-flowered ancestors within the Euphorbiaceae. Outside of parasitic ...

Ongoing molecular phylogenetic studies of cheilanthoid ferns confirm that the genus Cheilanthes (Pteridaceae) is polyphyletic. A monophyletic group of species within the hemionitid clade informally called the “C. marginata group” is here shown to be distinct from its closest relatives (the genus Aspidotis) and phylogenetically distant from the type species of Cheilanthes. This group is here seg...