Contemporary Circumscription Compared with A Utah Flora 4th ed.

Bio430

Saxifragaceae

Saxifragaceae, as defined in A Utah Flora, is a polyphyletic family used for conveniently stashing genera of uncertain affinity.  While “garbage bin” taxa such as this are convenient for some purposes, they poorly reflect evolutionary relationships and lack the predictability that natural classifications strive to obtain.  Of the genera listed in A Utah Flora, only the final 6 in the key (Mitella, Heuchera, Saxifraga, Lithophragma, Boykinia, and Saxifraga) are considered members of Saxifragaceae sensu stricto. 

Key Features

Hebaceous plants, mostly with basal leaves and scapiform inflorescences.  Flowers with hypanthia but stamens restricted to 5 or 10 (4 or 8) and the few pistils, when superior, free at the top but fused at the base.  Stipules present or lacking; when present, they are often along the petiole rather than strictly at the base.