Some years ago a corn breeder in the Middle West was surprised to find plants which did not have the normal green color, but were pure white. This strain of albino corn suddenly appeared in his otherwise normal seed stocks. Since they lacked green color, they could not use the energy of the sun to manufacture their organic food from water and carbon dioxide. Since no special provisions were made for their feeding, these albino plants died as soon as the food which had been stored in the seed was exhausted. This lack of color and therefore synthetic power was deadly to them. The strain could survive only when the mutation was covered by the dominant gene for color.

In the forests of Crater Lake are several plants which have solved the problem of survival without green color in a different manner. There exist in the duff of forests certain fungi which have the ability to digest cellulose and convert it to sugar. Since the sugars, as made, are outside the body of the fungus, they are available to any plant or animal in a position to absorb them. Since they are water-soluble, the roots of certain seed plants able to absorb and utilize them as a substitute source of organic material.

These plants are true seed plants which have secondarily lost their synthetic powers. Many of them have no close relatives among the green plants of the region and therefore must either have been derived from green plants at some distance from their present habitat or have survived less successful relatives. In the case of Pyrola aphylla, however, we can see the process of conversion to the non-green habit taking place. Several green species of Pyrola are found in the same range of Pyrola aphylla. There is indication of how recently the switch to non-green habit has occurred. The leafless stem of the flower-bearing shoot is green as it breaks thru the ground, and in some cases its color persists until the flowers are fully formed. It has the small amount occurring on the portion of the plant exposed to light, and thus capable of synthetic action, could not possibly support the extensive underground stem system that is two or four feet long.

Here is a step in the story of the seed plants. Similar plants show that some such process has occurred several times before. Thus it is not accidental occurrence, but a definite trend in development. It is possible that it is a process similar to that by which the fungi were derived from a precursor of our modern green algae millions of years ago.

It is not yet known whether these new seed plants are completely dependent on the action of fungi in rotting the duff or whether they are capable of carrying out this process for themselves. Strong presumptive evidence for the necessity of a fungal association comes from the observation that they are never found except where fungi are actively carrying on the process of decay. If, in the course of time, they do evolve the necessary mechanism to carry out the digestion of wood, they might supplant the fungi as decomposition agents of wood. In much the same way, in many habitats, the seed plants have replaced the dominant green vegetation such as ferns, which reproduce by spores.