that merely to mention their existence must suffice here. This close association of certain roots and bacteria, which, as we have seen, is of mutual advantage, is known as _symbiosis_. It is really only a kind of exchange, not unlike the storybook community that helped out by taking in each other’s washing. Unlike that community the association between the two works to the actual advantage of both, but the process is undeniably a step away from those wholly autophytic plants which live free and independent of such aid. A much more gruesome habit of certain plants is their reliance for food only upon the dead. In the Indian pipe, some kinds of shinleaf, and in many other plants their roots and root hairs are changed or often nearly lacking, and we find them growing only on the dead bodies of other plants. One peculiarly repulsive characteristic of such plants is that they secrete at their roots a substance that hastens the decay of the dead, and, as if this were not rapid enough, there are associated with them certain kinds of minute fungus organisms that also speed up decomposition. Plants with this charming mode of life are known as _saprophytes_, literally _sapros_, rotten, and _phytes_, plants. “Rotten plants” they may be in their mode of life, but the pearly white stems and flowers of the Indian pipe have a certain ghostly charm, an almost statuesque beauty among the normal greenery of the gloomy dark woods in which they always grow. It is not without significance that Indian pipe bears no leaves, has none or almost none of the life-giving green coloring matter which we have seen to be the almost priceless possession of plants which lead a different, and perhaps a better life. The great bulk of saprophytes bear no leaves, and some only partially wedded to the habit appear to be midway between bearing normal green leaves and bearing none, or much reduced ones that are quite unlike the busy factories we know normal green leaves to be. Plants with this method of getting their food, must of course grow in places where dead and decaying vegetation is plentiful, and often as such soil is turned up there may be noted a peculiar dank odor, suggestive not only of its origin, but of the fact that these “rotten plants” make their home in it. Some of our most beautiful orchids grow in this fashion, but even there, in spite of flowers that for beauty of form are without rivals, the plants have no green coloring matter in their leaves, which are often reduced or even wanting altogether.