National Capital Parks-East - Ferns

National Capital Parks-East (NACE) has documented 33 species of ferns and fern allies such as water ferns, horsetails, groundpines, salaginellas, and quillworts. State rare ferns known from NACE include the state threatened Glade Fern (Athyrium pycnocarpon) associated with the calcareous Shell Marl Ravine Forests of Piscataway and Fort Washington Parks and the state threatened Bog Fern (Thelypteris simulata) associated with the acidic soils of the Oxon Run gravel bog.