Medlar

medlar Mespilus germanica, a small tree of the rose family and a cousin of the apple. It bears an apple-like fruit, but this is open at the bottom end, exposing the five seed boxes.

Several varieties have been cultivated including a seedless one, but it is more common as a wild tree. The medlar can be grafted onto quince or pear stock, but does best on hawthorn stock, as Gerard (1633) noted:

The medlar-tree oftentimes grows in hedges among briars and brambles: being grafted on a white-thorn, it prospers and produces fruit three times as large as those which are not grafted at all, and almost the size of small apples. We have divers sorts of them in our orchard.