(_c_) Flowers with 4 sepals and 4 petals. Stem angular; leaves in whorls. =Rubiaceæ.= Stem round; leaves not in whorls. Stamens 6, erect. =Brassicaceæ.= Stamens 8, spreading. =Onagraceæ.= (_d_) Flowers with 5 sepals or petals, distinct. †Stamens as many or twice as many as the corolla lobes. Stems swollen at the nodes. =Caryophyllaceæ.= Stems not swollen at the nodes. Stem leaves numerous, entire, thin; flowers in terminal or axillary clusters, white or greenish. =Santalaceæ.= Leaves basal, entire; flowers solitary on a 1-leaved scape. =Parnassiaceæ.= Leaves mostly basal, lobed or cut; flowers in a close spike or head. =Saxifragaceæ.= Leaves and stems fleshy. Follicles 2. =Saxifragaceæ.= Follicles 4. =Crassulaceæ.= Leaves numerous, stiff, awl-shaped; stems low, tufted. =Saxifragaceæ.= ††Stamens more than twice as many as the corolla lobes. §Leaves basal or mostly so. Leaves evergreen, simple or lobed, flowers yellow or white, solitary on naked scapes. (_Dryas._) =Rosaceæ.= Leaves not evergreen, simple, lobed, or much divided. Smooth. Stems erect or floating. =Ranunculaceæ.= Stems creeping. Flowers white or pink. =Rosaceæ.= Flowers yellow. =Ranunculaceæ.= Rough-hairy. Flowers yellow or pink. =Rosaceæ.= Flowers white, blue or purple. =Ranunculaceæ.= §§Leaves mostly on the stem. Leaves finely cut; stems creeping; flowers white. =Rosaceæ.= Leaves entire. Leaves bright green, black-dotted; flowers yellow. =Hypericaceæ.= Leaves glaucous, without black dots; flowers blue. =Linaceæ.= (_e_) Flowers with 5 sepals and 5 united petals or lobes.