The foliage of the different varieties can often be distinguished by peculiarities of form and colour, and it varies considerably in the time of its appearance; in some hardly a leaf appears till the tree is in full bloom, while others produce their leaves so early as almost to hide the flowers.

The flowers differ in size and colour, and in one case in structure also, that of the St.Valery apple having a double calyx with ten divisions, and fourteen styles with oblique stigmas, but without stamens or corolla.
The flowers, therefore, have to be fertilised with the pollen from other varieties in order to produce fruit.

The pips or seeds differ also in shape, size, and colour; some varieties are liable to canker more than others, while the Winter Majetin and one or two others have the strange constitutional peculiarity of never being attacked by the mealy bug even when all the other trees in the same orchard are infested with it.
All the cucumbers and gourds vary immensely, but the melon (Cucumis melo) exceeds them all.

A French botanist, M.Naudin, devoted six years to their study.

He found that previous botanists had described thirty distinct species, as they thought, which were really only varieties of melons.