What is "saxifragaceous"

Saxifragaceous \Sax`i*fra*ga"ceous\, a. (Bot.) Of or pertaining to a natural order of plants ( Saxifragace[ae]) 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.

a. (context botany English) Of or relating to an order of plants (Saxifragaceae) of which saxifrage is the type.