The Collaborative International Dictionary of English v.0.48:

Miterwort \Mi"ter*wort`\, n. (Bot.)
   Any plant of the genus Mitella, -- slender, perennial herbs
   with a pod slightly resembling a bishop's miter; bishop's
   cap.
   [1913 Webster]

   False miterwort, a white-flowered perennial herb of the
      United States (Tiarella cardifolia).
      [1913 Webster]

WordNet (r) 3.0 (2006):

false miterwort
    n 1: plant with tiny white flowers hanging in loose clusters on
         leafy stems; moist woods from Alaska to central California
         and east to Montana [syn: false miterwort, false
         mitrewort, Tiarella unifoliata]
    2: stoloniferous white-flowered spring-blooming woodland plant
       [syn: foamflower, coolwart, false miterwort, false
       mitrewort, Tiarella cordifolia]