1Now in full "false mitrewort". A tiarella (foamflower), especially T. cordifolia.
2A mitella, especially M. diphylla.
3rare Any of several small tropical American herbaceous plants of the genera Mitreola and Cynoctonum (family Loganiaceae); especially Cynoctonum mitreola.
Late 18th century; earliest use found in Reinhold Forster (1729–1798). From mitre + wort, after the shape of the young fruit.