There are four types of peonies and they vary by shape. The progression towards fullness involves the stamens, anthers, carpels increasing in size from a single row of petals to complete fullness.

The single peony has a row of petals surrounding a center with two types of stamens which can be difference colors but are usually yellow.

Single varieties include: Athea, Dad, Krinkled White, Scarlet O’Hara, Sea Shell.

Japanese single peonies have a row of single petals with a center sporting large stamens and large anthers.

Japanese single varieties include:  Cheddar Surprise, Paramount, Doreen, Gay Paree, Nippon Beauty, Madame Butterfly.

Semi-Double peonies have two rows of outer petals with small inner petals of irregular size.

Varieties include:  Coral Charm, Coral Supreme, Coral Fay, Paula Fay, Miss America, Buckeye Belle.

Bomb type peonies have at least one row of outer petals with a ball, or bomb cluster of petals above consisting of petaloids derived from both carpels and stamens.

Varieties incude:  Mons Jules Elie, Red Charm, Raspberry Sundae, Charlie’s White, Mr. Ed, Duchess de Nemours.

Double peonies have full rows of petals covering the entire flower center.  The center can only be seen in some cases when the flower is fully open.

Varieties include:  Mrs. F.D. Roosevelt, Festiva Maxima, Sarah Bernhardt, Gardenia, Kansas, Henry Bockstoce, Dinner Plate, Edulis Superba, Princess Margaret.