This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
There are many species of Birch, but perhaps none to equal in beauty and value the common silver or white-barked Birch of the British Islands (B. alba), which attains a height of 50-80 ft. in favoured localities. Young plants from 1 1/2 - 7 ft. high are sold in thousands every year either for home or foreign plantations. There are several varieties, including albo-pur-purea, the leaves of which are rich purple above, white beneath; laciniata, leaves deeply cut; pendula Youngi, the Weeping Birch; variegata, leaves blotched with white, and others. The North American Paper Birch (B. papyracea) grows 60-70 ft. high, and also has a white bark.