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THE TINTS AND SHADES IN AUTUMN WOODS. 
P. Q. KEEGAN, LL.D., 
Patterdale, Ulleswater. 
It has been observed with regard to the autumnal colours exhibited 
by American trees, more especially the maples of New England, that 
‘a medium amount of moisture and late frost seem to be favourable 
to the greatest brilliancy in leaves ; while, on the other hand, early 
frost and a great degree of moisture are distinctly unfavourable to 
the production of the effect.’ It is well known that some American 
maples, scarlet oaks, and chestnuts display in the fall a depth and 
vividness of colouration which is never seen in Great Britain. Even 
marked changes of colour as they exhibit in their native habitats. 
Nevertheless, it is true that those British forest trees whose foliage is 
conspicuous in the autumn for even a tolerably fair show of crimson, 
scarlet, or bright yellow, are nearly allied to, if not specifically 
identical with those American ones which are eminent for brilliancy 
of autumnal livery. Hence it may be suspected that the structure 
of the particular leaf itself has something to do with the alternative 
of their being either vividly tinted, or otherwise, in the fall. The 
particular point of structure of the leaf here concerned would seem 
to be what is called its consistency, i.e., its texture, so to speak, 
which, according to the name-burdened text-books, may be either 
“herbaceous, ie, thin and flaccid, or succulent, coriaceous, OF 
fleshy” This ‘consistency’ seems to be connected not only with 
the Capacity of particular leaves for the retention of water, but also 
with the greater or less lignification of their cell walls, ie., their 
Power of forming compounds with the tannin, etc., contained in the 
Sap. Where the leaf is thin, crisp, and dry, as in the beech, maple 
Mahonia, etc., there the process of lignification seems to be some- 
what arrested, the cell-walls would seem to remain clear and not 
Clogged with phlobaphenes and compounds of tannin, with gum, or 
Proteid substances. Hence on the fall of the leaf in the autumn the 
ted colouring matter formed in solution in the sap shines through 
Cell, as it were, and is not obstructed in its manifestation, SO that 
Aer we have a petal-like exhibition of colour. In some cases, ne 
those of the mountain ash, wild cherry, etc., where ordinarily 22 
leaves in fading become yellowish passing to brown, they under 
influence of an exceptionally dry season turn red, Just a5 1S a a 
with many usually pure white flowers turning pink under Oe ae 
— cumstances, These exceptional cases may be explained by 
Nov. 1897. x 
