THE NATURALIST.

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RAINING TREES.

(By John Murray, Esq.  F.S.A. &c.)

The secretions of trees form a curious part of their physiology, but the influence of vegetation on the atmosphere seems to have been entirely overlooked, at least as far as it regards its meteorology.

In the case of that curious genus of plants the Sarracen_ia_, in which the S. adunca is most conspicuous, the foliaceous pouch is a mere reservoir, or cistern, to catch and retain the falling dew or rain.  In the Nepenthes distillatoria, or pitcher plant, the case is different; and analysis proves it to be an evident secretion from the plant itself, independent altogether of the fact that it is found in the pitcher before the lid has yet opened.  I may here state, en passant, that the results, I obtained from a chemical examination of this liquid differ materially from those of Dr. Edward Turner.  The Cornus mascula is very remarkable for the amount of fluid matter which evolves from its leaves, and the willow and poplar, when grouped more especially, exhibit the phenomenon in the form of a gentle shower.  Prince Maximilian, in his Travels in the Brazils, informs us that the natives in these districts are well acquainted with the peculiar property of those hollow leaves that act as recipients of the condensed vapours of the atmosphere; and, doubtless, these are sources where many tropical animals, as well as the wandering savage, sate their thirst “in a weary land.”  The Tillands_ia_ exhibits a watery feature of a different complexion:  here the entire interior is charged with such a supply of liquid, that, when cut, it affords a copious and refreshing beverage to man.  That these extraordinary sources of “living springs of water” are not unknown to inferior creation, is a fact interestingly confirmed to us in the happy incidents detailed by Mr. Campbell, in his Travels in South Africa, where a species of mouse is described to us, as storing up supplies of water contained in the berries of particular plants; and, in Ceylon, animals of the Simia tribe are said to be well acquainted with the Nepenthes distillatoria, and to have frequent recourse to its pitcher.  The mechanism of the “rose of Jericho” (Anastatica hierochuntina] shows the susceptibility of plants to moisture in a very remarkable manner; and I have submitted some experiments made with this extraordinary exotic, the inhabitant of an arid sandy soil, to the Horticultural Society of London.  That succulents should be found clothing in patches the surface of the burning desert is a phenomenon not the least wonderful in the geographical history of vegetation.