“An assemblage of plants that has been selected for a particular character or combination of characters and that is clearly distinct, uniform, and stable in these characters and that when propagated by appropriate means retains those characters (ICNCP Art. 2.3).”
International society for horticultural science. International Code for the Nomenclature for Cultivated Plants, Ninth Edition. Scripta Horticulturae 18. Eds. Brickell, C.D., Alexander, C., Cubey, J.J., David, J.C.