Shrub or woody vine

        Woody vine; petals 7 or more........................Decumaria

        Shrub; petals 4 or 5

                Leaves alternate or on short spur branches

                        Leaves pinnately veined; ovary superior...................Itea

                       Leaves palmately veined; ovary inferior..................Ribes

                Leaves opposite

                        Petals usually 4; stamens 20-40....................Philadelphus

                        Petals usually 5; stamens 8-10.......................Hydrangia

Herbs

        Staminodia present; petals more than 10 mm long............Parnassia

        Staminodia absent; petals less than 10 mm long

                Leaves ternately decompound......................................Astilbe

               Leaves simple

                        Flowers solitary in leaf axils, or in short, leafy cymes

                                Sepals 4; carpels 2.........................Chrysosplenium

                                Sepals 5; carpels 3..........................Lepuropetalon

                        Flowers in racemes or panicles

                                Petals pinnatifid or fringed; stem leaves opposite..........Mitella

                                Petals not pinnatified or fringed; stem leaves alternate or absent

                                        Ovary 1- celled

                                                Inflorescence paniculate; stamens 5...........Heuchera

                                               Inflorescence racemose; stamens 10...............Tiarella

                                        Ovary 2-celled

                                                Stamens 5; leaves palmately lobed...............Boykinia

                                               Stamens 10; leaves not palmately lobed.......Saxifraga
 

                                                                                               (Radford, Ahles & Bell)