Nature Notes

Volume XIII No. 1 - October, 1947

A Visitor Learns About Lichens
By Gordon P. Walker, Ranger-Naturalist

"Ranger, is that sulphur on those rocks over there?"

"No, sir, the bright yellow color which you see is a lichen."

"A lichen? What in the world is that?"

"A lichen is a form of plant life which results from a combination of a fungus and an alga. Any one of a number of fungi may combine with a single alga or any one of these fungi may combine with several different algae. Each one of these combinations results in a separate species of lichen having a distinct color and form. Both of these factors are a result of the interaction of the two members of this relationship and rarely, if ever, do they resemble either the alga or the fungus as it grows alone. The color seems to be connected with special chemical compounds, each produced only by a single pair."

"Does just any old fungus and alga, as you call it, get together in this way?"

"So far only one group of fungi have been found in lichen associations of the temperate region. These are the cup fungi or Ascomycetes. In the tropics, fungi closely related to the toadstools also combine in this way. Three kinds of algae are found in lichens; brown, blue-green, and more commonly green algae. Ordinarily only the single-celled algae combine, but occasionally a filamentous form has succeeded in doing so. Scientists have been able to break them down into their two components and grow them separately in the laboratory, they have never been able to recombine the two under artificial conditions."

"Why should the two combine anyway? Wouldn't' they compete with each other?"

"On the contrary, in nature they help each other out. You see, the fungus is an excellent water absorber and it also can get a grip almost anywhere, but it lacks the ability to make its own organic food. The alga, having green color just like the grass or trees, can use the energy from the sun in the manufacture of sugar. Some of this sugar goes to the fungus which in turn gives the alga a good environment in which to live. In this way the two of them together are able to live in very difficult places such as the surface of bare rock, where neither of them could singly. In fact they are the first form of life to invade any new rock formation and to the all important first work in the breaking down of rock to soil."

"Hmm, right out on bare rock, eh? Do they grow anywhere else?"

"Yes, the forms which grown on trees, you would call mosses. The yellow moss on the trunk of that hemlock there is one called the stag horn lichen. Although it grows on the trees, it is in no sense a parasite. It may get some mineral material from the dead outside bark to which it is attached, but it does not penetrate into the living tissue of the old tree and derives no organic foodstuff from the tree. It grows equally well on living and dead trees or branches. You will notice that it doesn't grow down to the ground in very many places. This is because it doesn't do well when it is buried underneath lasting winter snows. Thus the bottom of the lichen growth indicates the level of the normal persistent snow. At lower elevations there is another lichen, the goat's beard, which grows in the same manner on the same trees. It looks somewhat the same but the color is lighter and it usually is somewhat longer. At around 5,200 feet there is a sharp line where the goat's beard suddenly gives way to the stag horn which we see up here."

"The black moss which hangs so thickly on the lower limbs of the alpine fir there to your right is known as the squaw's hair lichen. I have been told that it was used as a famine food by the Indians. Deer eat it in wintertime, but in summer it is a hazard, since it burns readily and a tree will literally explode if humidity is low and a match or other flame is touched to it. Another edible form, called rock tripe, grows on the rocks up the trail. Other forms grow on down logs and some flat on the ground."

"Golly are there many of these things?"

"Yes, although many of them have not been identified as yet, there are probably from seventy to a hundred of them in the park and the known forms throughout the world number in the thousands. Some of them are exquisitely delicate and others are brilliantly colored, such as the one which splashes the northeast side of the Phantom Ship with gaudy orange. If you are interested in them, go up the Garfield trail where you will see the rocks covered with veritable gardens of them. They are particularly showy right after a rain. The moisture seems to bring out their colors as they blossom out into renewed growth."

(Much of the information contained in this article was obtained by private communication from Dr. F. P. Sipe, Associate Professor of Botany, University of Oregon.)

The purpose of a National Park is to protect and preserve in a primitive, a natural state, the most significant examples of floral and faunal types; as well as of scenery, so that scientist, nature lover, and the general public may see, enjoy, learn and benefit.

Evolution In Action
By Gordon P. Walker, Ranger-Naturalist

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.

The Future Wizard Peninsula
By L. T. Grose, Ranger-Naturalist

The Watchman-Hillman talus slopes form the largest single slide area within the caldera walls. The slide is constantly in action, though no mass slumps have occurred in the last few years. The coarse, flat, detrital beach at the base grows rapidly outward in Skell Channel. It has been built up as follows: Perennial snow patches remain at the base of the talus. Most of the detritus slides over the snow and is deposited farther out on to the beach or into the water. In the early summer when the snow is deepest, the rocks are carried into the water. Already the beach extends 300 feet into Skell Channel. The Channel is now approximately 1,600 feet wide and less than 100 feet deep.

The earliest pictures of Crater Lake, about 50 years old, do not show any such wide beach. Wizard's status as an island is endangered; if the present rate of erosion continues and the lake level does not rise, our great grandchildren will view Wizard Peninsula.

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