Although, as I have said, the sycamore is remarkably free from disease and from serious fungoid or insect attacks, it is the host of a parasitic fungus which seldom fails to make its presence apparent, though without perceptibly affecting the growth or health of the tree. Readers must be very familiar with the circular black spots which appear on the leaves about midsummer and continue till they fall. It is not a few leaves or a few trees here and there that are so affected, but all the leaves on large trees and on every tree in the wood. The difficulty is to find a leaf without these black spots; so that people have come to regard them as part of the regular colour scheme of the foliage. Nevertheless, each of these blots is a colony of the parasitic fungus, _Rhytisma_, whereof the life-history is still subject for investigation. It is not evident how the colonies are regularly distributed, each clear of the other, all over the leaves of a lofty tree, nor how, seeing that they fall to the ground with the leaves in autumn, the fungus manages to get access in the following summer to the loftiest branches. It is lucky that, being so widely distributed and existing in such incalculable numbers, these colonies do not appreciably interfere with the natural functions of the sycamore. The only native species of maple in Britain is the Field Maple (_Acer campestre_), which does not extend naturally into either Scotland or Ireland, though it grows freely in both these countries when planted in either of these countries. It is a very ancient element in the woodland of south Britain, its remains having been identified in pre-glacial beds in Suffolk. It has no qualities to recommend it for ornamental planting, and the timber, once highly prized by British cabinetmakers, has been ousted from the home-market by imported foreign woods. When the Rev. William Gilpin, author of a well-known work on _Forest Scenery_, died in 1804, he was buried, it is said, at the foot of a field maple growing in his own churchyard at Boldre, in the New Forest. Strutt gave a figure of this tree which he described as the largest of the species in England; but he gives the height as only 45 feet, whereas Elwes records several from 60 to 70 feet high.