This section is from the book "Commercial Gardening Vol3", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
The Apple is far and away the most important of hardy fruits grown by market gardeners in the British Islands. Originally springing from the Wild Crab Apple (Pyrus Malus), fig. 329, it has undergone such a transformation in the course of centuries of cultivation and selection that the many excellent varieties now known bear but very little resemblance to their wild progenitor except in mere outline. The fruits of the Wild Crab Apple are 1 in. or a little more in diameter, yellowish when ripe, and bitterly sour in flavour. The leaves are 1 to 2 in. long, oblong-rounded in shape, tapering at the apex, and irregularly toothed on the margins; and the umbels of pink-and-white flowers usually appear in May.
Being distributed in a wild state throughout the temperate regions of the Northern Hemisphere, it is natural that a good deal of variation should exist, and to this circumstance is probably due the fact that in the hands of the gardener the Crab Apple has lent itself so readily to modification and improvement. For generations such improvements as took place were purely accidental, the result of chance seedlings, and the history of some of the oldest known varieties is lost in obscurity.
Fig. 329. - Crab Apple (Pyrus Malus). (J).
It is said that the "Old English Pearmain" is the oldest known English Apple on record, having been cultivated in Norfolk before the year 1200-The "Costard Apple", which is said to have given the name of costard-monger or costermonger to vendors of it, was known in the thirteenth century; while other old English Apples, like the Catshead, the English Codlin, Golden Pippin, Golden Reinette, the Joanetting, etc, were not recorded until the sixteenth and seventeenth centuries.
It was not, however, until the end of the eighteenth and the beginning of the nineteenth century that anything like a systematic attempt was made in England to improve the different varieties of Apple. Thomas Andrew Knight (born 10 October, 1758, died 11 May, 1838), paid special attention to the Apple, and infused a spirit of higher methods of cultivation and selection into the pomologists of his clay. Since his time still greater advances have been made. Gardeners have a far better knowledge of the principles underlying hybridization and cross-fertilization, and more scientific methods are adopted for raising new varieties of excellence. Notwithstanding this, it must be admitted that many of the older kinds of apples, about whose parentage little or nothing is known, are still in the front rank. In private gardens a far larger variety of kinds is to be found than in market gardens, for the simple reason that once the latter are planted, from 50 to 100 years or more may elapse before newer and better varieties may take their place.