Today I finally found a fern that I’ve been trying to find for several years. While not rare in NY, rusty woodsia (Woodsia ilvensis) can be difficult to find because it prefers to grow in crevices in rocks. In central NY suitable habitat for this fern is restricted to rocky cliffs surrounding mountain summits. Even after finding the plants, getting close enough to photograph them proved to be a challenge. Fortunately there were a few plants that were accessible with a little careful maneuvering.
The plants are rather small. The largest fronds were not more than 5 or 6 inches in length.
The common name comes from the appearance of the fertile fronds which are reddish-brown on the underside.
The rusty appearance comes from the color of the sporangia and a mixture of scales and long hairs that turn rusty-brown at maturity.