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OUTLINES OF BRITISH FUNGOLOGY.

is one of the most remarkable phenomena amongst Fungi,and without example amongst other plants. It sometimes,however, proceeds from a mycelium, and in the end alwaysgives rise to fruit-cells, and sometimes to spiral tissue, andis therefore by itself no sufficient reason for excluding theseproductions from the rank of vegetables.

The colour of Fungi-depends in most cases upon the con-tents of the cells, except in those instances where the walls ofthe cells themselves are carbonized. These contents are ofalmost every colour except a pure green. When green occursin Fungi, as in Peziza eeruginosa, Agaricus aruginosus, etc.,it is generally of a metallic hue, or dull and inclined to olive,as in the green Russula.

I notice, in conclusion, under this head, one or two pro-perties occasionally exhibited by Fungi. The most notableof these is the luminosity of some species. Agaricus olearius,for instance, which grows on olive-trees in the south ofFrance, is so luminous that it is possible to distinguish lettershv its light, and still more luminous species have been foundin Brazil, Australia, and Amboyna. We are not, how r ever,without luminous Fungi in this country, but the pheno-menon is rare, and has been observed principally in imper-fectly developed species. Decayed wood and leaves also aresometimes luminous, but whether from the presence of fun-gous matter or not, is not quite certain.

I am not aware that in these cases there is any accessionof heat, hut Dutrochet has observed that more heat is gene-rated by Boletus <eneus occasionally than by any other vege-table.

It has been asserted that powerful odours are destructiveto Fungi, and especially that of Russian leather; but I donot find this confirmed by my own experience, at any rate asfar as regards the instance alleged.