Recent increase in commercial breeding in the genus Aster of cultivars particularly suitable for the cut-flower industry calls for a reassessment of the systematics of cultivated asters. A system of three cultivar-groups is proposed here to encompass most of the diversity of cultivars based on typical user criteria: the Dumosus Group, the Universum Group and the Novi-belgii Group. The applicability of numerical character analysis for cultonomic classification is outlined. The flexibility of open (‘cultonomic’) classifications for culta is demonstrated. It is shown that this system of cultivar-groups serves stability much better in the application of names to Aster cultivars than the continued use of Latin binomials. The use of the culton concept and its consequences for classifying Aster cultivars is outlined.