A woodland fern in France developed from two plants from separate species which diverged 60 million years in the past. Genetic analysis revealed the heritage of the vegetative life form.
Normally, plants and animals from different species can not interbreed and create viable offspring, especially those separated for such vast periods of time. This hybridization is being compared to a human successfully mating with a lemur.
The fern was discovered in the Pyrenees Mountains in France, and brought to a nursery. There, researchers examined the plant, and extracted DNA for analysis. They found the unusual organism was a cross between a fragile fern and an oak fern. Although those two species are commonly found throughout the northern hemisphere, they have not interbred for 60 million years, researchers determined.
"To most people they just look like two ferns, but to fern researchers these two groups look really different," Carl Rothfels from the University of California, Berkeley said.
Although such interbreeding is highly unusual, this is not the first time that such a mating has been observed in nature. Tree frog species, genetically separated by 34 million years, were found to breed, as well as Sunfish species who diverged 40 million years in the past. In most plants and animals, however, just a few million years is required before the species are incapable of reproducing and forming viable young.
Ferns reproduce using sperm and eggs, as do many life forms. However, unlike many plants which require pollinators such as bees and birds to reproduce, the process in ferns relies on just water and wind in order to carry spores. This quality could explain why ferns are capable of reproducing across species - they are not hindered by animals who may not visit plants with unusual flowers or other unfavorable characteristics.
Ferns and other plants that do not rely on animals to reproduce may evolve genetic incompatibilities as quickly as those species which utilize sex. Although ferns have existed on Earth for a far longer period of time than flowering plants, they are outnumbered 30 to one by the other class of vegetation.
The group of ferns first evolved around 360 million years ago, long before the rise of dinosaurs. Today, roughly 12,000 species of the plants are found around the world. However, many of our modern species of the plants are not found in the fossil record until 145 million years ago.
Discovery of the unusual cross-hybridization of the French fern was detailed in the journal American Naturalist.