shield fern

from The Century Dictionary.

• noun Any fern of the genus Aspidium: so called from the form of the indusium of the fructification. The sori or fruit-dots are roundish and scattered or arranged in ranks; the indusia are solitary, roundly peltate or kidney-shaped, fixed by the middle or edge. For further characterization, see Aspidium.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of various ferns of the genera Dryopteris or Polystichum or Lastreopsis having somewhat shield-shaped coverings on the sori