Abstract

The ornamental crop crown imperial, Fritillaria imperialis L., belongs to Fritillaria section Petilium (Liliaceae) and consists mainly of very old cultivars, the oldest being more than 400 years old. Recently, an increase in commercial breeding efforts within Fritillaria section Petilium resulted in new cultivars suitable for the garden and for cut-flower production. These new cultivars are not only produced within the species F. imperialis but are mostly interspecific hybrids between the four species of section Petilium (F. chitralensis, F. eduardii, F. imperialis, F. raddeana). As a result of this interspecific hybridisation the cultivars show a mix of characteristics of two or more species and a classification based on the taxon concept, necessitating the introduction of new hybrid taxa, does not seem desirable. For the existing cultivars (within species) and the new developed cultivars from interspecific hybridisation, a new classification based on the culton concept is developed. Fifteen morphological characteristics were observed for all four species of section Petilium, for most of the cultivars of F. imperialis and F. eduardii, and for the cultivars developed by interspecific hybridisation. From the results of these morphological observations it was clear that the cultivars of F. imperialis and the interspecific hybrids have the same morphological characteristics and belong to one crop. We discuss two ways to make Groups within this new crop and describe the present status of the F. imperialis cultivars which are still in culture.