Dryopteris marginalis - Leather Woodfern
A dark green leathery looking fern that is evergreen. The fronds come out of the root crown in a circle and then layout somewhat. Needs soil that is rich, humus, and moist. It grows in a clump and the clump will get larger but it is very slow to spread so it will work well in with your other flowers.
Shade, Rich Moist Soil, 2-3 ft Tall, Zones 3-8