Peony Flower Forms Some authorities, particularly Chinese growers have invented numerous titles to describe the shape of Peony flowers. In the book ‘Chinese Tree Peony’ written by The Peony Association of China, there are listed no less than 13 forms for Tree Peonies alone. Whilst none can gainsay the experience and dedication of the Chinese in these matters, most Western authorities rely on fewer forms and the descriptions which follow are derived from respected books, widely available in the West. Click on any image to see a larger, named version.
The Single Form: Those flowers in which one or maybe two rows of petals surround the stamens and anthers in the centre. Most of the Peony species have flowers of this form.
 The Japanese Form: Flowers with one or two rows of outer petals, but the majority of the stamens have  been  converted into narrow stamenoids which are petal-like.
Primevere Bowl of Beauty
 The Anemone Form: Flowers in which all of the stamens have been converted to stamenoids, sometimes these  are quite wide. The term is often replaced by the Japanese Form. 
Belle Center
 The Semi-double Form: Flowers in which a possibly reduced number of stamens are scattered through the flower,        sometimes in circles and alternating with the petals.
Mrs Franklin D. Roosevelt
The Crown Form: Flowers may also be described as ‘double’. The outer row of petals becomes very distinct as the flower ages, leaving a centre dome of slightly raised petals.
Eden's Perfume
The Bomb Form: Extremely double flowers, often very heavy which makes them tend to need support. A very large number of petals are present, rising in the centre to form a distinct high mound as the flower ages.
The Peony Society