Hydrangeaceae

Deciduous woody shrubs. Leaves opposite, simple, toothed along edges, stalked; stipules none.

Flowers in cymes or racemes in leaf axils or at the ends of branches, white or pale pink, appearing after the leaves have expanded, very showy and fragrant in Philadelphus. Most flowers are fertile, producing both pollen and seeds, and radially symmetrical. Some of the outer flowers in Hydrangea (or rarely all of the flowers) are sterile, producing neither pollen nor seeds and symmetric only when divided 1 way (bilaterally). Sepals usually 4 or 5 in fertile flowers, 3-4 in sterile flowers; in Hydrangea, the fertile flowers are small and have tiny sepals, while the sterile flowers consist only of large, petal-like sepals. Petals in fertile flowers 4 or 5, separate. Stamens 8 to many. Carpels 2-5, fused to form 1 pistil with 1 ovary; ovary located below the point of attachment of other flower parts (inferior); styles 1-5; stigmas 2-5. Fruit a capsule.