Definition of black spleenwort in English:

black spleenwort

noun

  • Either of two small ferns commonly found on rocks and walls, maidenhair spleenwort, Asplenium trichomanes, and (now more usually) the Eurasian fern A. adiantum-nigrum, which has triangular fronds with a dark base to the stem.

Origin

Late 18th century; earliest use found in Stephen Robson (1741–1779), botanist.