Rock Polypody

Here is another Species Spotlight I have written for the Poughkeepsie Journal and the Preserve's Social Media. Hopefully, you'll see another one in the news!

Rock Polypody Ferns

On a stroll around Laurel Ledge Road, the cliffs are starting to be decorated with beautiful patches of ice and icicles. Along with the winter in its full swing, other plants and animals are hammering down to battle the declining temperatures and cold extremes.

Looks Like: Rock polypody are ferns with leaf blades widest near the middle of the frond. The blades are leathery and lobe-shaped with blunt tips. They have scales on their rhizomes that can be two shades of brown.

Rock Polypody Curled Up Leaves
Found on Laurel Ledge Road
Mohonk Mountain House, New Paltz, NY

Lives On: They can be found all year long hugging north-facing rock contours and woody forests in rich, subacid, moist, shallow soils, even in winter. They prefer rocks, boulders, cliffs, and ledges.

Niche: Rock polypody is a small but dense growing fern that traps leaf litter and other organic material which provides for a substrate for other flowering plants and shrubs to grow.

Threats: Plants that are on ledges and boulders are inaccessible to Deer are the safest to predation. At times in the winter, Deer can be seen trying to get to them and heavily browse on the little evergreen ferns. Also, these plants can become threatened when recreational visitors travel heavily amongst the rock scrambles or navigate to approaches for climbing and bouldering. The plants tend to get trampled when visitors create their own access vistas off trail, so it is important to use already set trails provided by the Preserve when recreating on the grounds.

Frequency: In the Shawangunks, it is found quite commonly on the tops of talus boulders and on shaded ledges. These plant communities are vigorous, evergreen ferns that can be seen on the tops of the largest undisturbed and remote boulders and on some ledges are thought to be among some of our oldest relict plants.

Reproduction: Reproduces by spores and vegetatively by rhizomes. The spores are grouped together on the leaves in structures called sori, but can be at times found on a separate structure called a fertile front. The sori can be found on the underside of the blades. The sori are covered or shielded by a flap-like structure that protects the spore until dispersal is triggered.

Fun Facts: Rock Polypody Fern leaves will curl up when temperatures get really cold and the dew point drops very low. Air temperature was down to single digits when this photo was taken during a Conservation Science Field Trip around the Mohonk Preserve. Polypody ferns are exposed to many environmental and climate extremes, in order to survive the very dry and very cold desiccating conditions, leaves will curl up to keep in moisture and retain nutrients to the core of the plant. Remarkably, they will revive when conditions allow. Plants much find ways to battle the freezing temperatures; curling up sounds pretty good during this cold winter!

This is one fern of some six families, 18 genera, and 41 species documented in the 135 square mile Shawangunk Mountain Study Area where records have been kept and studies made for nearly 90 years.