[
Ferns of the Columbia River Gorge of Oregon and Washington
]
Spreading Woodfern, Spreading Wood Fern, Northern Woodfern
Dryopteris expansa
Synonyms:
Dryopteris assimilis
,
Dryopteris dilatata
,
Dryopteris dilitata
var.
americana
,
Nephrodium expansum
A tripinnate frond.
Paul Slichter
