Page:Popular Science Monthly Volume 16.djvu/842

. The light, however, is usually emitted by the organs of reproduction; this is particularly the case in young fungi, while, in the older ones, after the luminosity has disappeared from the gills, the surface of the stipe becomes radiant.

The mycelium of the root-shaped fungi (rhizomorpha) penetrates through the decaying organic matter of wood and coal deposits, exhibiting a clear pale light. This has been particularly observed in the mines near Dresden, Hesse, and occasionally in England. These flowerless, gleaming plants impart a weird beauty to the caverns of granitic rock in Bohemia, illuminating them with a pale mimicry of moonlight.

The most remarkable instances of cryptogamic phosphorescence have been noted by Mr. Gardner in Brazil, by Dr. Cuthbert-Collingwood in Borneo, by Mr. Hugh Low and James Drummond in Australia, and by Mr. Worthington-Smith in the Cardiff coal-mines. Rev. J. M. Berkeley cites an instance in England, where a dazzling radiance was observed upon a spruce or larch log, which continued for several days—a byssoid mycelium, yielding an unusually pungent odor, being recognized. The common potato also, in decomposing, generates a peculiarly luminous parasite; and, at one time, an alarm of fire was sounded in the streets of Strasburg from the light produced by a decaying mass stored in a cellar. An instance has recently come to my notice, where a brilliant light was thrown off by pieces of cantaloupe, after a few hours' exposure to the air.

Wherever, then, we encounter decomposing vegetable matter, we observe some form of fungi living upon and appropriating the changed substances of a former condition to the generation of a new life. What, therefore, seems to us a loss or waste, is merely change—change of form, change of condition. The absorbing roots of these parasites grow into the tissues of the host in the most intimate manner, deriving from a disorganization of the substances the elements necessary to their own being.

Vergil describes the blighting mildew on the grain as "an unbidden crew of graceless guests that choke the fields"; and De Barry writes that there is a frequent unbidden guest in every household, who lays under contribution its stores of sweets. The mold or mildew which gathers on the surface of preserves is a plant of exquisite beauty when viewed with low magnifying power and by reflected light, for what appears to the naked eye only a soft, white, woolly crust, becomes a glittering forest of graceful stems and branches, standing like fine spun silver upon the dark background of the supporting surface. This substratum is in reality a mycelium, or system of fine interlacing, thread-like roots, which form the vegetative part of the plant, and are woven into a soft, black or brown velvety substance, through which run russet, scaly hairs. The branches rise to about the fiftieth of an inch, and bear the fruit and seed-cells. Higher microscopic power