Single Dahlias feature blooms with a single row of flat or slightly cupped ray florets arranged in a flat plane, uniformly overlapping, preferably in the same direction with no gaps. The disc flowers may have up to three rows of bright yellow or orange pollen and the blooms are over two inches in diameter (5 cm).
Mignon Dahlias possess the same formation as Single Dahlias except they have round ray floret tips, their disc flowers have no more than two rows of pollen and their blooms are under two inches in diameter.