The Collaborative International Dictionary of English v.0.48:

Saxifragaceous \Sax`i*fra*ga"ceous\, a. (Bot.)
   Of or pertaining to a natural order of plants
   (Saxifragaceae) of which saxifrage is the type. The order
   includes also the alum root, the hydrangeas, the mock orange,
   currants and gooseberries, and many other plants.
   [1913 Webster]