The Collaborative International Dictionary of English v.0.48:

Saxifrage \Sax"i*frage\ (?; 48), n. [L. saxifraga, from
   saxifragus stone-breaking; saxum rock + frangere to break:
   cf. F. saxifrage. See Fracture, and cf. Sassafras,
   Saxon.] (Bot.)
   Any plant of the genus Saxifraga, mostly perennial herbs
   growing in crevices of rocks in mountainous regions.
   [1913 Webster]

   Burnet saxifrage, a European umbelliferous plant
      (Pimpinella Saxifraga).

   Golden saxifrage, a low half-succulent herb
      (Chrysosplenium oppositifolium) growing in rivulets in
      Europe; also, Chrysosplenium Americanum, common in the
      United States. See also under Golden.

   Meadow saxifrage, or Pepper saxifrage. See under
      Meadow.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Chrysosplenium americanum
    n 1: aquatic herb with yellowish flowers; central and western
         United States [syn: water carpet, water mat,
         Chrysosplenium americanum]