On the forest floor in the mountains of France, scientists from Duke University and the University of California, Berkeley have discovered the hybrid fern of a ferns separated 60 million years ago. Kathleen Pryer and Carl Rothfels published in the March 2015 issue of American Naturalist the story of ×Cystocarpium roskamianum, the sterile offspring of two ferns that last produced progeny 60 million years ago. The recognition of such a union is akin to an elephant hybridizing with a manatee or a human with a lemur. Divergence over time produces genetic inconsistencies that prevent species from again trading genes to produce offspring. Extremes in divergence are rare. There are, however, documented crosses after 34 million years (tree frog) and 40 million years (sun fish) but 60 million years has sent the botanical world buzzing. For most plant and animal species a few million years is all that is needed to inhibit hybridization. The speciation clock in ferns may run more slowly perhaps explaining why flowers outnumber ferns 30 to 1. In the mean time the spores of love drift again for the oak fern (Gymnocarpium) and the fragile fern (Cystopteris) in the forested mountains of France after a 60 million year separation. Jerry
That's interesting...and something I really haven't thought about, except in humans. Now I have to look up how the tree frog evolved.
That's so interesting Jerry. I can't see any logical explanation other than this. 60 million years is such a long time
