Ferns and Lycophytes of Muddy Run

After finishing work with Morgan on the morning of the 15th, I decided to turn northward along the Susquehanna to look for a different set of ferns. The mica-schist ranges of the River Hills provide dry, acid rock crevices, judiciously fed by seepage permeating through the outcrops, which favor Asplenium montanum and its allopolyploid descendants A. bradleyi and A. pinnatifidum. In the early 20th century, the hybrid A. × gravesii (A. bradleyi × pinnatifidum) was several times reported, but A. bradleyi itself is pretty hard to find these days. I know of some good spleenwort sites on local preserves, such as Kelly's Run and Tucquan Glen, but I also wanted to seek out some less-visited areas that might still harbor undiscovered treasures.

First, I checked on a known locality on the York County side of the river; a fallen tree made it tricky to access part of the site, but A. pinnatifidum and its backcross with A. montanum, A. × trudellii, were still occupying their familiar ledges, together with the usual tufts of A. montanum tucked into dry ledges and an A. platyneuron above in the woods.

From there, I headed up the river to visit the Muddy Run Wildlife Management Area. Muddy Run, a historic locality for spleenworts, has been dammed to form a pumped storage reservoir. However, the valley below the reservoir is not only preserved, but publicly accessible.

My initial foray down-valley seemed disappointing. Unlike the narrow gorges at Tucquan Glen or Benton Hollow, there didn't seem to be much outcrop in the hillsides. Ferns were the pretty standard woodland ones of the area; I didn't find marginal wood fern, a common haunter of rocky hillsides, until much further downvalley, testifying to the deeper soils.

As I bushwhacked around on the steep slopes downvalley, trying to avoid bouncing several hundred feet downhill onto the Port Road, outcrops and a xeric, acid forest began to reveal themselves. The reptiles were out in force, a box turtle and garter snake making their appearance. After photographing a chestnut stump sprout near a large outcropping, I tracked down some A. montanum in its crevices. There wasn't much else around...until I found a smaller outcrop nearby that was hosting a nice small colony of A. pinnatifidum. Dutifully crossing a valley and inspecting some more outcrops, I finally found the real prize of the day: a new station for A. bradleyi. It was probably known to the old-timers, but not reported anytime recently. Sadly, I didn't see any little plantlets around it; just an evergreen tuft clinging to its little niche in the schist. Still, it's always thrilling to be able to report another example of this rare fern.

Posted on July 21, 2018 11:16 PM by