The International Society for Horticultural Science (ISHS) and their designated registrar for the genus Paeonia (Peonies), the American Peony Society (APS) recognizes 6 distinct flower forms for peonies which are as follows: Single, Japanese, Anemone, Bomb, Semi-double and Double flower form. Flower anatomy and flower form are an inherited trait and therefore constant throughout the plants of any given cultivar. The flower form is a cultivar specific trait. In newer, less established plantings, blossoms can appear smaller in size, with fewer petal count and the flower form can be variable. The plant produces a reduced flower at a young age or if stressed at a mature age. As the bush matures over time or stress factors are eliminated, the blossoms will advance in development and gain the typical flower form associated with a particular cultivar.