This section is from the book "Wild Flowers Of The North American Mountains", by Julia W. Henshaw. Also available from Amazon: Wild Flowers of the North American Mountains.
Rootstock: stout, ascending, chaffy. Leaves: firm, broadly-oblong, lanceolate, acute at the apex. Sori: large, borne near the midvein.
This fern grows in the woods to a height of three feet. It is a handsome plant, springing from an ascending root, and has rather coarse leaves.
Aspidium spinulosum var. dilatatum, or Spinulose Shield Fern, has a stout root, and long, rather thin leaves, the lower pair of which are triangular in outline.
Aspidium Oreopteris, or Scaly Shield Fern, has very scaly, straw-coloured stems and rachis. The leaves are one to two feet long, and taper from near the middle to both ends.
 
Continue to: