Cystopteridaceae and the Cystopteris fragilis complex

One of the main taxonomic groups that we focus on is Cystopteridaceae, the ecologically diverse and globally distrbuted fern family that includes Cystopteris (the fragile ferns, bladder ferns, and bulblet fern), Acystopteris, Gymnocarpium (the oak ferns), and xCystocarpium (the CystopterisGymnocarpium hybrid).

Cystopteridaceae contains a gloriously distressing array of polyploid complexes with taxa ranging from diploid (two chromosome sets) to octaploid (eight sets), particularly in the infamous “Cystopteris fragilis complex.”

Our research with Cystopteridaceae seeks to use this family as a model to understand polyploid (and reticulate) evolution, especially at macroevolutionary timescales. To do so, we taken an integrative approach, relying heavily on fieldwork and on diverse sorts of data (molecular data, morphological data, cytogenetic data, etc.)

Diploid (a), tetraploid (b), and hexaploid (c) members of the Cystopteris fragilis complex. For each example the whole plant is shown, as well as a micrograph of the spores showing differences in spore size, and a corresponding chromosome squash.