Definition of rusty woodsia in US English:

rusty woodsia

noun

  • The fern Woodsia ilvensis (family Athyriaceae), of northern regions of North America, Europe, and Asia, which has a reddish-brown scaly coating on the undersurface of its fronds.

Origin

Mid 19th century; earliest use found in Henry David Thoreau (1817–1862), author and naturalist.