: The frond consists of 6 to 14 pairs of triangular, toothed leaflets. The lowest pair are often the largest, and they gradually decrease in size toward the tip.
Bradley's spleenwort is highly specialized and is often referred to as an "Appalachian spleenwort". bradley's spleenwort
Bradley's spleenwort - Illinois Department of Natural Resources : The frond consists of 6 to 14
Due to its very specific habitat requirements and rare occurrence, it is considered a species of special concern in many states. bradley's spleenwort