The common fruit trees of Europe - apples, pears, cherries, plums and so on generally carry flowers that have male and female parts.
For fruit to form, the female part (pistil) must receive pollen from the male part (stamen) of another flower preferably from a different but compatible variety of the same species.
So a Discovery won't pollinate another Discovery, but there are other apple varieties that will. And no apple will pollinate a pear or a cherry or a plum, irrespective of variety.
There is one important detail: the two trees must be in flower at about the same time. So you can check this, most fruit trees are arranged into "pollination groups". Those groups define which varieties are both compatible and in flower at the same time.
If you are interested in finding a pollination partner for a particular variety, why not use our online Pollination Checker which will do the work for you?
There are 3 types of fruit tree when it comes to pollination:
These detailed lists of pollination partners are divided into groups to make choosing a partner easy:
Apple Trees.
Cherry Trees.
Pear Trees.
Plum, Gage, Damson, Mirabelle, Bullace Trees - these will all pollinate each other.