Not much and the name Jonquil is used regionally rather than botanically. In general jonquils are more often fragrant and always yellow. Daffodils come in several colors but both are considered in the Narcissus family (along with thousands of other varieties.) The best way to tell the difference is to look at the tips of the leaves. Jonquils have more slender leaves with rounded ends. Daffodils have wider leaves that are sharp like a sword at the end. Care for both is the same and they both flower in the spring. Jonquils are more often grown in the South and other warmer areas as daffodils do best with colder winters. Keep growing, Marianne Binetti