The Collaborative International Dictionary of English v.0.48:

Kidneywort \Kid"ney*wort`\, n. (Bot.)
   (a) A kind of saxifrage (Saxifrage stellaris).
   (b) The navelwort.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Navelwort \Na"vel*wort`\, n. (Bot.)
   A European perennial succulent herb (Cotyledon umbilicus),
   having round, peltate leaves with a central depression; --
   also called pennywort, and kidneywort.
   [1913 Webster]