Ferns climbed aboard trees to experience flowering of their own species diversity

Washington, July 3 (ANI): Scientists have constructed a new time-calibrated family tree for ferns, which has indicated that while modern tropical rain forests were becoming established, ferns climbed aboard, and experienced a flowering of their own species diversity.

The family tree for ferns was created by Duke University researcher Eric Schuettpelz, along with associate professor Kathleen Pryer.

Though ancient, it appears that ferns really came into their own during a very hot, very wet period that peaked about 10 million years after the Cretaceous/Tertiary boundary 65 million years ago.

"Two key innovations may have led to the ferns' success in the face of the new competition from flowering plants," Schuettpelz said.

Some ferns developed the ability to make a living on light that was more toward the red end of spectrum. Around this time, some ferns also developed the ability to live on trees, sometimes without soil, as epiphytes.

By storing water, developing thicker skin, or being more tolerant to drying out, the epiphytic ferns could now perch on a trunk, limb, or twig and live quite happily more than 100 feet off the forest floor, where moisture, temperature, and sunlight are very different indeed.

Whereas the fossil record seemed to suggest that ferns experienced three distinct pulses of species diversification, the Duke team's analysis shows that there was a fourth, roughly corresponding with the development of epiphytism.

So, as rain forests developed and tropical trees and vines clawed past each other to reach heavenward, they took the ferns up along with them.

Thousands of new fern species evolved to take advantage of all the new niches being created in the canopy.

"In some ways I guess, the epiphytes escaped the battle on the ground," Schuettpelz said.

Today, epiphytes comprise about 30 percent of the more than 9,000 living fern species. (ANI)