Medium-sized fern with elongate fronds about a foot long. Each leaf (frond) made of paired leaflets that are not quite opposite each other. Each leaflet is lobed or divide into subleaflets, which are, in turn, lobed. Spores are born in structures called sori on the underside of the leaflets. These are white early on (bottom row, center), but darken and open up when the spores mature, as below.

A fern of moist rocky cliffs, especially limestone ones.  It is native to most of the US, except for the southeast, as well as across Canada and coastal Greenland.  It is usually seen in the spring, and often disappears in dry summers, only to re-emerge in the fall,. Rare in Wildwood, growing in rocky sections of the banks of Connelly's Run.

This species was earlier mistakenly identified as C. fragilis, Fragile Fern, but that species does not occur in Virginia.  I thank the people of iNaturalist for setting me straight.  The species is similar to Bulblet Bladder Fern (Cystopteris bulbifera), and grows in similar habitats, but that species has little green bulbs growing on the leaves and the staliks.  Little bulbs are often lacking on the Tennessee Fragile Fern, but if they occur they are misshapen and dark colored, not green.