Classification of cultivated plants.

Agricultural practice demands principles for classification, starting from the basal entity in cultivated plants: the cultivar. In establishing biosystematic relationships between wild, weedy and cultivated plants, the species concept needs re-examination. Combining of botanic classification, based on biosystematic research, and agricultural classification starting from the cultivar, into one unequivocal classification system for cultivated plants, is urgently needed. This is illustrated by the often obscure position of cultivated hybrid