Sunday, September 11, 2011

Edna's Trillium

Edna and John Garst have a cabin on Lake Yonah, an old Georgia Power reservoir in northeastern Georgia's Tallulah-Tugaloo drainage, which forms with the Chattooga River, the headwaters of the Savannah River.  Lake Yonah sits in a small gorge, Georgia on the west, South Carolina on the east.   One day they boated over to Battle Creek Ravine in South Carolina.   Edna noticed a small white-flowered trillium that she had never seen.  

When they returned to the cabin, she checked her wildflower books, but none of the trilllium pictures looked like the trillium flower she had seen at Battle Creek.   Later, when she and John told Dr. Wilbur Duncan, a botanist at the University of Georgia in Athens (their home base) about the plant, Dr. Duncan said he vaguely remembered finding something like the Battle Creek trillium in nearby Tallulah Gorge years earlier.

A few years later, a description of Trillium persistens (persistent or Edna's trillium) appeared in Rhodora, the Journal of the New England Botany Club, in English and, as required by botanical science, in Latin.   The little white trillium Edna found that day was a new species!

Trillium persistens is a small white trillium endemic to Georgia and South Carolina.   Its entire range is included in the southern portion of the Tallulah-Tugaloo drainage in Tallulah Gorge and tributaries and small gorges to the south.   Edna's trillium is what biogeographers call a "narrow" endemic.

Was it more widespread in the distant past?   Or is this trillium a relatively new plant that has speciated in the ravines and gorges of northeastern Georgia and northwestern South Carolina?   It is difficult to know; possibly, future studies on the DNA of it and related species will shed more light on its origin.

But thanks to the sharp eyes of Edna and John, we now know that this small woodland beauty is rare (it is listed as endangered by the U. S. Fish and Wildlife Service--it even appeared on a postage stamp a few years ago) and local.   And every time we find the plant in Tallulah Gorge or a nearby ravine, we know we are looking at something unique.

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