The Duke cherries, long placed by most pomologists and botanists in a botanical variety of Prunus avium, are unquestionably hybrids between the Sweet Cherry and the Sour Cherry. A study of the characters of the varieties of the Duke cherries shows all gradations between Prunus cerasus and Prunus avium, though, in the main, they resemble the latter more than the former, differing from the Sweet Cherries most noticeably in having an acid flesh. Sterility is a common attribute of hybridism. In this respect the Dukes behave like most hybrids. In several Duke cherries all of the seeds collected at this Station are sterile; in others, most of them are sterile and in none are the seeds as fertile as in varieties known to be pure bred as to species. So, too, shrunken pollen grains indicate hybridity. A study of the pollen of the Duke cherries shows many grains, the greater proportion, to be abnormal, a condition not found in the pollen of varieties true to species. May Duke, Reine Hortense and Late Duke are the leading hybrid varieties.
There are dark colored Duke cherries with reddish juice and light colored sorts with uncolored juice, just as in the two parent species. May Duke is a typical variety with colored juice while Reine Hortense is probably the best-known cherry among these hybrids with uncolored juice. About 65 of the cherries listed in The Cherries of New York are "Dukes,"or hybrids between the Sweet and the Sour Cherry.
The name Duke comes from the variety May Duke which is a corruption of Medoc, a district in the department of Geronde, France, from whence this variety came. The cherries of this group are known as Dukes only in England; in France the name Royale is similarily used.
These hybrid cherries have been placed in a distinct botanical group by several botanists. They constitute the Cerasus regalis Poiteau and Turpin (Traite des Arb. Fruit. 123); the Cerasus bigarellaregalis Roemer (Syn. Monogr. 3:69); and the Prunus aviumregalis Bailey (Cyc. Am. Hort. 1453-1901).
Abbesse d'Oignes Arch Duke Choisy May Duke Other Dukes with individual descriptions