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ters 4 and 5. Careful observation of flowering cherries forms the basis for a successful classification as proposed in the key that follows. Classification Key This classification key is not exhaustive. It focuses on Japanese flowering cherries of the Prunus serrulata group and some closely related cherries commonly found in Western countries. A few rarer forms, but only easily recognized ones, are also mentioned in the key. All the cherries in the key have, as a rule, corymbose inflorescences, acuminate leaves (most have an acute or even aristate serration), large and thick flower buds, narrow sepals that usually do not reflex over the calyx tube, and often large single or double flowers. If the cherry to be classified does not have corymbs, that is, if the pedicels of its flowers are not borne on a stalk (peduncle) but appear from the bud on the twig in an umbel, it is more likely to be a form of Prunus sargentii, P. Ă—yedoensis, or something similar to P. 'Accolade'. If the flowers in an umbel have a pitcher-shaped calyx, and if the pedicels are pubescent, the cherry is likely to be a form of P. pendula or P.Ă—subhirtella. Cherries with umbellate inflorescences are not covered in this key. The differences between garden cultivars are often slight and can vary according to site or even weather. One way to avoid some problems has been to define more than one characteristic per step and to allow for a choice among three options at some points. After determining the classification of a plant by using the key, one always needs to verify other botanic details with the description of that cultivar in the text. Key 1. Petals 510 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Petals 1020 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Petals 2050 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Petals more than 50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 2. Flowers with 5 petals usually, only occasionally with more than 5 petals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Flowers with 610 petals usually, only occasionally with 5 petals . . . . . . . . . . .17 3. Flowers white when fully opened . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Flowers pink or flushed pink when fully opened . . . . . . . . . . . . . . . . . . . . . . . .13