Page:Popular Science Monthly Volume 16.djvu/841

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807
VEGETABLE PHOSPHORESCENCE.

The phosphorescence of fungi has been observed in various portions of the world. Rumphius first noticed its appearance in Amboyna in a species of corticium to which the name Telephora cærulum was given. Under this specific name are grouped many minute forms of fungi, only the mycelium of which were known to Linnæus and Agardh, the discovery of other organs forming the complete plant being of more recent date.

Among mushrooms four of the genus Agaricus are luminous, and have been examined with special reference to this effect by Delille, Fabre, and Tulasne: The red or orange-colored species (Agaricus olearius), inhabiting the adjacent soil or roots of olive-trees in Central Europe; the fire-mushroom, or Agaricus igneus, which Rumphius discovered in Araboyna; the Agaricus noctilucus, found at Manila by Gandichaud; and Agaricus Gardineri of the Brazilian provinces, growing upon the dead leaves of the Pindoba-palm. The red mushroom of the olive-trees is wonderfully beautiful. The gills curve out from the pedicle and expand under the pileus into a trumpet-or bell-like form of almost vermilion hue, which changes at night into a pale blue light, gleaming, where they are massed together, like blue bells of fire.

M. de Candolle erroneously supposed that the phosphorescence of the Agaricus of the olive occurred only at the time of its decomposition. M. Fries, with equal error, attributed the effect to the presence of a secondary parasite; Tulasne, however, denies that the seat of light is in the mold, and states that he has observed the phosphorescence of the plant itself. He agrees with Delille in regarding the appearance as limited to the period of growth, and refers to it as a "manifestation of vegetation." M. Delille supposed the radiance to be intermittent, while M. Fabre observed that exposure to the sunlight appeared to have no influence whatever upon the phenomena, and that the light was exhibited at any time under cover of darkness. Dr. Phipson, in reviewing M. Fabre, remarks that this seems, however, to indicate that the light of the sun has in reality an influence upon the emission of light during the daytime, and that the phenomenon is probably a case of phosphorescence after insolation. But as we know the Agaricus belongs to that class of colored parasites which are destitute of green foliage, and consequently of proper digestive organs of their own, and draw support from the elaborated products of the foster-plant, the phosphorescence may be accounted for as the result of chemical action under conditions where the influence of solar light is not required to produce a higher combination.

Tulasne recognized that the light was not confined exclusively to the reproductive surfaces, and proved by dissection that the whole mass offered scintillations. This is probably due to a sympathetic or highly vitalized condition of the whole plant during the process of fecundation, as is indicated by the juice of the phosphorescent euphor-