Page:The Strand Magazine (Volume 3).djvu/291

 single Alp being greater than that of an entire lowland landscape (unless a view from some Cathedral tower); add to this charm of redundance that of clearer visibility—tree after tree being constantly shown in successive height, one behind another, instead of the mere tops and flanks of masses, as in the plains; and the forms of multitudes of them continually defined against the clear sky, near and above, or against white clouds entangled among their branches, instead of being confused in dimness of distance."

There is much that is interesting in the relations of one species to another. Many plants are parasitic upon others. The foliage of the beech is so thick that scarcely anything will grow under it except those spring plants, such as the anemone and the wood buttercup or goldylocks, which flower early before the beech is in leaf.

There are other cases in which the reason for the association of species is less evident. The Larch and the Arolla (Pinus cembra) are close companions. They grow together in Siberia; they do not occur in Scandinavia or Russia, but both appear in certain Swiss valleys, especially in the cantons of Lucerne and Valais and the Engadine.

Another very remarkable case which has recently been observed is the relation existing between some of our forest trees and certain fungi the species of which have not yet been clearly ascertained. The root tips of the trees are, as it were, enclosed in a thin sheet of closely woven mycelium. It was at first supposed that the fungus was attacking the roots of the tree, but it is now considered that the tree and the fungus mutually benefit one another. The fungus collects nutriment from the soil, which passes into the tree and up to the leaves, where it is elaborated into sap, the greater part being utilised by the tree, but a portion reabsorbed by the fungus. There is reason to think that, in some cases at any rate, the mycelium is that of the truffle.

The great tropical forests have a totally different character from ours.

Sir Wyville Thomson graphically describes a morning in a Brazilian forest:—

"The night was almost absolutely silent. Only now and then a peculiarly shrill cry of some night bird reached us from the woods. As we got into the skirt of the forest, the morning broke, but the reveil in a Brazilian forest is wonderfully different