After 60 million years apart, two fern genera form hybrid in the mountains of France

March 9, 2015, University of Chicago
Cystocarpium roskamianum is a recently formed hybrid between two parents that last shared a common ancestor approximately 60 million years ago. Credit: Harry C. Roskam

In an article published in the March 2015 issue of The American Naturalist, a team of researchers report on a fern from the French Pyrenees that is a recently formed intergeneric hybrid between parental lineages that diverged from each other approximately 60 million years ago.

The hybrid —×Cystocarpium roskamianum—was found growing wild in the mountains of France and is sterile, but can reproduce itself vegetatively and grows well in cultivation.

Rothfels et al.'s finding that two fern lineages are still able to hybridize after nearly 60 million years of divergence is surprising evidence for an extraordinarily deep hybridization event—one that is roughly akin to an elephant hybridizing with a manatee, or a human with a lemur.

As populations become separate, their members are thought to lose the ability to interbreed relatively quickly, usually within a few million years. This process—the evolution of reproductive isolation—is critical for the formation of , and understanding the rate at which it evolves is of great interest.

That a species of oak fern (Gymnocarpium) could cross with a fragile fern (Cystopteris) to produce a viable hybrid after such a long time apart suggests that ferns may evolve reproductive incompatibilities much more slowly than most animals or flowering plants. If a slower "speciation clock" for ferns is true, it might explain why there are only around 10,000 fern species on Earth today, compared with around 300,000 species of flowering plants, without any need to invoke competitive advantages of per se.

Explore further: Distant species produce love child after 60 million year breakup

More information: Carl J. Rothfels, Anne K. Johnson, Peter H. Hovenkamp, David L. Swofford, Harry C. Roskam, Christopher R. Fraser-Jenkins, Michael D. Windham, and Kathleen M. Pryer, "Natural Hybridization between Genera That Diverged from Each Other Approximately 60 Million Years Ago." The American Naturalist Vol. 185, No. 3 (March 2015), pp. 433–442.

Related Stories

Ferns borrowed genes to flourish in low light

April 14, 2014

During the age of the dinosaurs, the arrival of flowering plants as competitors could have spelled doom for the ancient fern lineage. Instead, ferns diversified and flourished under the new canopy—using a mysterious gene ...

Herbivore defence in ferns

November 21, 2012

(—Unlike flowering plants, bracken ferns do not release any odour signals to attract the enemies of their attackers for their own benefit.

Ferns may hold key to land rehabilitation

March 6, 2015

Ferns may have potential in rehabilitating land following work by WA researchers who investigated how ferns are able to survive in semi-arid environments of Australia.

Recommended for you

How quinoa plants shed excess salt and thrive in saline soils

September 21, 2018

Barely heard of a couple of years ago, quinoa today is common on European supermarket shelves. The hardy plant thrives even in saline soils. Researchers from the University of Würzburg have now determined how the plant gets ...

Basking sharks can jump as high and as fast as great whites

September 20, 2018

A collaborative team of marine biologists has discovered that basking sharks, hundreds of which are found off the shores of Ireland, Cornwall, the Isle of Man and Scotland, can jump as fast and as high out of the water as ...

Decoding the structure of an RNA-based CRISPR system

September 20, 2018

Over the past several years, CRISPR-Cas9 has moved beyond the lab bench and into the public zeitgeist. This gene-editing tool CRISPR-Cas9 holds promise for correcting defects inside individual cells and potentially healing ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.