| Noun | 1. rock brake - any of several small lithophytic ferns of tropical and warm temperate regionscliff brake, cliff-brakefern - any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by sporesgenus Pellaea, Pellaea - genus of chiefly small rock-loving ferns; in some classification systems it is placed in the family Polypodiaceae or Adiantaceaecoffee fern, Pellaea andromedifolia - evergreen fern of California and Baja CaliforniaPellaea atropurpurea, purple rock brake - very short shallowly creeping North American fern usually growing on cliffs or walls and having dark glossy leaf axesbird's-foot fern, Pellaea mucronata, Pellaea ornithopus - cliff brake of California and Baja California having purple-brown leafstalks | | 2.rock brake - dwarf deciduous lithophytic fernsfern - any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by sporesCryptogramma, genus Cryptogramma - sometimes placed in family Polypodiaceae or CryptogrammataceaeAmerican parsley fern, American rock brake, Cryptogramma acrostichoides - rock-inhabiting fern of northern North America growing in massive tufts and having fronds resembling parsleyCryptogramma crispa, European parsley fern, mountain parsley fern - fern of Europe and Asia Minor having short slender rhizome and densely tufted bright green fronds resembling parsley | | 3. rock brake - chiefly lithophytic or epiphytic fern of North America and east AsiaAmerican wall fern, Polypodium virgianum, rock polypodypolypody - any of numerous ferns of the genus Polypodium |