Cryptogramma acrostichoides is a fern species in the Cryptogrammoideae subfamily of the Pteridaceae. It is known by the common names American parsley fern and American rockbrake and is native to most of western North America, where it grows in the cracks of rocks in many types of mountainous habitat.
Cryptogramma acrostichoides grows in a tuft from a rhizome. There are two leaf types. The sterile leaf has flat, oval-shaped lobed leaflets resembling parsley, and the fertile leaf is longer with narrow, thick, linear leaflets with their margins curled under to cover the sporangia on the undersides.