(JANUARY)

THE LITTLE OLD MAN OF THE ROCK

Some say it was Leif Ericson, some say it was Columbus, but I say it was The Little Old Man of the Rock.

And I go further. I say he not only discovered America but Europe, Asia, and Africa, and the islands of the sea. I'll tell you why.

I. How Little Mr. Lichen Discovered the World

As everybody knows, we must all eat to live, and how could either Columbus or anybody else—except Mr. Lichen—have done much discovering in a world where there was nothing to eat? When the continents first rose out of the sea[2] there wasn't anything to eat but rock. Rock, to be sure, makes very good eating if you have the stomach for it, as Mr. Lichen has. It contains sulphur, phosphorus, silica, potash, soda, iron, and other things that plants are fond of, but ordinary plants can't get these things out of the rock—let alone human beings and other animals; and that's why Mr. Lichen had the first seat at the table and always does.

On bare granite boulders in the fields, on the rocky ruins at the foot of mountains, and even on the mountain tops themselves, on projecting rocks far above the snow line, you find the lichens. On rock of every kind they settle down and get to work. They never complain of the climate—hot or cold, moist or dry. When the land goes dry they simply knock off, and then when a little moisture is to be had they're busy again. A little goes a long way with members of the family who live in regions where water is scarce. Indeed, most of them get along with hardly any moisture at all. The very hardiest of them are so small that a whole colony looks like a mere stain upon the rock.

While lichens are generally gray—they seem to have been born old, these queer little men of the rock—you can find some that are black, others bright yellow or cream-colored. Others are pure white or of various rusty and leaden shades. Some are of the color of little mice. To make out any shapes in these tiny forms, you must look very close; and if you have a hand lens you will be surprised to find that this fairy-land of the lichens isn't so drab as it seems to the naked eye. For there are flower gardens—the tiny spore cups. Some of them are vivid crimson and, standing out on a background of pure white, they're very lovely. Some of the science people believe the colors attract the minute insects that the lens shows wandering around in these fairy flower gardens. But just what the insects can be there for nobody knows, since the lichens are scattered, not by insects, but by the wind.

As a rule lichens grow only in open, exposed places, although some are like the violets—they enjoy the shade. Some varieties grow on trees, some on the ground, others on the bleached bones of animals in fields and wastes and on the bones of whales cast up by the sea.

Of course the whole country was awfully wild when the continents first came out of the sea, but that just suited Mr. Lichen, for there is one thing he can't stand, and that is city life, with its smoke and bad air.

"Why, one can't get one's breath!" he says.

WHY THE LICHENS DISLIKE CITY LIFE

So, while you will not meet Mr. Lichen in cities—at least, until after the people are all gone; that is to say, on ruins of cities of the past—you will find him beautifying the ancient walls of abbeys, old seats of learning like Oxford, and the tombstones of the cities of the dead.

Mr. Lichen always travels light. On the surface of the lichens are what seem to be little grains of dust, and these serve the purpose of seeds. A puff of wind will carry away thousands of them, and so start new colonies in lands remote.

You see, the fact that he requires so little baggage must have been a great advantage to Mr. Lichen in those early days, when he had to discover not only America but all the rest of the world map, spread out so wide and far. You can just imagine how the grains of lichen dust, the seed of the race, must have gone whirling across the world with the winds.

But if a breath of wind would carry them away so easily, how could they stay on a rock, these tiny lichen travellers? Especially as they have no roots? They have curious rootlike fibres which absorb food by dissolving the rock, and this dissolved rock, hardening, holds them on. The fibres of lichens that grow on granite actually sink into it by dissolving the mica and forcing their way between the other kinds of particles in the rock that they can't eat. Thus they help break it up.

As we all know, little people are great eaters in proportion to their size, but it is said the lichens are the heartiest eaters in the world. They eat more mineral matter than any other plant, and all plants are eaters of minerals.

Yet, you'd wonder what they do with the food they eat—most of them grow so slowly. A student of lichens watched one of them on the tiled roof of his house in France—one of the kind of lichens that look like plates of gold—and in forty years he couldn't see that it had grown a single bit, although he measured it carefully.

HOW MR. LICHEN EATS UP STONES

But how could such feeble creatures, as they seem to be, ever eat anything so hard as rock? Well, they couldn't if it wasn't for one thing—they understand chemistry. At least they carry with them, or know how to make, an acid, and it's this acid which enables them to dissolve the rock so that they can absorb it. The acid is in their fibres—what answer for roots. And the dissolved rock not only gives them their daily bread, but, as I said a moment ago, holds them on. This use of acid is their way of eating; chewing their food very fine, and mixing it with saliva, as all of us young people are taught to do.

The first and smallest of the lichen family spread and decay into a thin film of soil. This decay makes more acid, just as decaying leaves do to-day—they learned it, no doubt, from the lichens—and this acid of decay also eats into the rock and makes more soil. (You see nature, from the start, has been helping those that help themselves, just as the old proverb has it.) Then, after the first tiny lichens—mere grains of dust that have just begun to feel the stir of life—come somewhat larger lichens which can only live where there is a little soil to begin with. These in turn die, which means a still deeper layer of soil, still more acid of decay, and so on up to larger lichens and later more ambitious plants. Then, on the soil made by these successive generations of lichens, higher types of plants—plants with true roots—get a foothold.

Besides making soil themselves, the lichens help accumulate soil by holding grains of rock broken up by their fibres and loosened by the action of the heat and cold of day and night and change of season. These little grains become entangled in the larger lichens and are kept, many of them, from being washed away by the heavy rains. So held, they are in time crumbled into soil by the action of the acids and by mixture with the products of plant decay. To this day, go where you will, over the whole face of the earth, and you'll find the lichens there ahead of you, dressed in their sober suits, some gray as ashes, others brown, but some are as yellow as gold; for even these old people like a little color once in a while. As travellers they beat all.

"Their geographical range is more extended than that of any other class of plants."

That's how the learned lichenologists put it. For these lichens, these humble little brothers of our dust, that many of us never looked at twice on the stones of the field, or the gray stumps and dead limbs in the wood, are so interesting when you've really met them—been properly introduced—that a whole science has grown up around them called "lichenology." And exciting! You ought to hear the hot discussions that lichenologists get into. You read, for instance, that such and such a theory "was received with a storm of opposition" (as most new theories are, by the way, particularly if they are sound).

But the tumults and the strifes of science, of politics, or of wars don't disturb little old Mr. Lichen himself. There on his rock he'll sit, overlooking the scenery and watching life and the seasons come and go for 100, 200, 500 years, and more. For while they grow so slowly the lichens make up for it by living to an extreme age.

THE LICHENS AND THE ROMAN EMPIRE

Why, do you know that during the lifetime of certain lichens that are still hale and hearty, not only a long line of CÆsars might rise, flourish, die, and, with their clay, stop holes to keep the wind away, as Mr. Shakespere put it, but the vast Roman Empire could and did come into being, move across the stage with its banners and trumpets and glittering pomp and go back to the dust again.

Some lichens, growing on the highest mountain ranges of the world, are known to be more than 2,000 years old!

II. The March of the Trees

Of course I don't mean to say it takes any 2,000 years for the average lichen to die and turn to dust. These long-lived lichens are the Methuselahs of their race. Most kinds die much younger, as time goes among the lichens, and in a comparatively few years, a century say, after their first settlement on the rock, the lichens have become soil. All this time the heating of the rock by day and the cooling off at night, the work of frost and the gases of the rain and the air[3] have also helped to make more soil and by and by there is enough for lichens of a larger growth; and mosses begin to get a foothold. These, in turn, die and, in decaying, make acids, as did the little lichens before them, and this acid joins hands with all the other forces to work up the rock into soil. Presently there is enough soil to let certain adventurers of the Weed family drop in. The picking is very thin, to be sure, but some of these Weed people have learned to put up with almost anything. Don't suppose, however, that all weeds are alike in this respect. Oh, dear, no! They come into new plant communities just as the trees do, not haphazard, but according to a certain more or less settled order. Some of them, the adventurer type, will, it is true, settle down and seem contented enough on land so poor that to quote the witty Lady Townshend "you will only find here and there a single blade of grass and two rabbits fighting for that"; while other weeds will have nothing to do with soil that, in their opinion, is not good enough for people of their family connections.

It has long been known that the character of soil may be told, to a considerable degree, by the kind of weeds that grow on it. An old English writer pointed this out in his quaint way some 200 years ago:

"Ground which, though it bear not any extraordinary abundance of grass yet will load itself with strong and lusty weeds, as Hemlocks, Docks, Nettles and such like, is undoubtedly a most rich and fruitful ground for any grain whatsoever."

But, he goes on to say:

"When you see the ground covered with Heath, Broom, Bracken, Gorse and such like, they be most apparent signs of infinite great barrenness. And, of these infertile places, you shall understand, that it is the clay ground which for the most part brings forth the Moss, the Broom, the Gorse and such like."

Wherever soil is coarse and bouldery the weeds also are of a sturdy breed. In his long, delightful days among the mountains Muir[4] tells us what a brave show the thistles made in this new world of soil; how royal they looked in their purple bloom, standing up head and shoulders above the other plants, like Saul among the people.

HOW PLANT PEOPLE PAY THEIR TAXES

In all these plant republics each citizen must pay something into the common treasury for its board and keep. This fund not only meets "national expenses" during the lifetime of the ones who pay these taxes, but it helps prepare the land for the great citizens of the future—the trees. In another hundred years—making two hundred in all, after the arrival of the very first lichens—low shrubs and bushes often find spots in these new communities where the soil is thick enough for their needs.

It is very curious how members of the plant world, growing side by side, seek their food at different depths, and send out their roots accordingly. It reminds one of the rigid class distinctions below stairs in a nobleman's household where the chef has his meals in his own private apartment, the kitchen maids in their quarters, the chauffeurs, footman, under butler, and pantry boys in the servants' hall.

But most striking, it has always seemed to me, is the settled order in which trees march into the land. Why shouldn't the oaks come before the maples? Or the maples before the beeches? Or the beeches before the pines? Why is it that, with the exception of a straggler here and there, the first trees to climb the stony mountainsides are the pines? Then close behind come such trees as the poplars, and along the streams below, the willows. Still farther down the valley are the beeches; farther still the maples, and last of all the oaks.

So it is they advance in a certain regular way, each in its own place in the ranks. At first it seems as strange as the coming of Birnam wood to Dunsinane that gave poor Macbeth such a turn that time. But, after all, the explanation is quite simple and no doubt you have guessed it already.

The reason such trees as the pines, poplars, and willows come first is that the seeds are so light they are easily carried by the winds and so reach new soil ahead of other trees with winged seeds like the beeches and the maples; for, although these seeds also travel on the wind, they are much larger than the winged seeds of the pine and they travel much more slowly and for shorter distances.

Moreover, at the end of their first journey, having once fallen to the ground, they are apt to stay. Then there is no further advance, so far as these particular seeds are concerned, until trees have sprung from them and they, in turn, bear seeds. In the case of very light seeds, like those of the pines, the wind not only carries them far beyond the comparatively slow and heavy march of the beech and the maple, but if they fall on rock with little or no soil the next wind picks them up and carries them farther, so that they may strike some other spot where there is soil and perhaps a little network of grass and weeds to secure them until they can take root and so hold their own. It is not only a great advantage to the pine seeds to be so small, so far as getting ahead of other trees is concerned, but it is an advantage in another way. Because they are so small they require comparatively little soil to start with, are more easily covered up, and so they soon begin to sprout. The very winds that carry them up among the mountain rocks are quite likely to cover them with enough dust to start on, and I myself have helped raise many a giant of the mountain forests in this way. It is really wonderful how little soil a pine-tree can get along with; if, say, its fortunes are cast on some mass of mountain rock. Somehow it manages to get a living among the cracks and at the same time to hold its own in the bitter struggle with the winds.

"The pine trees," says Muir, "march up the sun-warmed moraines in long hopeful files, taking the ground and establishing themselves as soon as it is ready for them."

Last of all come tramping along the sturdy old oaks and the nut-bearing trees. Their seeds are so heavy they get little help from the winds, and then only in the most violent storms. They must advance very slowly indeed, with occasional help from absent-minded squirrels who carry away and bury nuts and acorns and then forget where they put them.

ROUGH CITIZENS AMONG THE PIONEERS

The beginnings of a forest are stunted because the soil is thin. Moreover, the company in which the trees find themselves is very miscellaneous, like the population of all pioneer communities—weeds, grasses, briers, shrubs. High up on a mountainside you can find all these types of vegetation. Pines growing clear to the snow line; farther down the mountain, in crannies, sumach and elder bushes with field daisies and goldenrod scattered among them; while on the barren rocks are the lichens and the mosses.

Not only do the citizens of the plant world follow a certain fixed order in coming into new regions, but also in giving place to one another. All plants of a higher order can live only on the remains of those of a lower, and it is most interesting to note the process by which each lower form comes, does its work, passes on, and is replaced by a superior type. The shrubs, which can only grow after the weeds and grasses have made enough soil for them, at length shade out these smaller pioneers. Haven't you often noticed, when picnicing in deep woods, that the grasses and flowers are to be found only in the sunny spaces, where there are no trees?

But these thickets themselves, after a while, disappear, and pines take their places. I am speaking now of the growth of forests, where the soil-making has so far advanced that forests are possible. The thickets, with their good soil and the shade which keeps it damp, are just the places for the pine seeds brought in by the wind to get a foothold and sprout up. When they grow into big trees they gather with their high branches so much of the sunshine for themselves that little of it gets through to the shrubs below, so these shrubs disappear, surviving only in the sunny open spaces or along the borders of the wood.

But now notice what happens to the pines. When the trees become larger, the young pines that spring up beneath their shade can't get enough sunshine, so, as the big trees grow old and die, there are fewer and fewer young pines to take their places. Now comes the turn of the spruces. For spruces require more and better soil than the pines and they don't mind a reasonable amount of shade. So, as the woods grow thicker and shadier, the pines gradually disappear and the spruces take their places.

At first, in the reign of the spruces, some of the old residents begin to come back. A spruce forest, not being so dense in the beginning as a pine forest, lets in a good deal of sunlight, and you'll find scattered through its aisles and byways gentians, bluebells, daisies, goldenrod.

In course of time, however, the leaves and branches of the spruces become so thick that hardly a sunbeam can get through and you have a forest where noontime looks like twilight; a forest of deep shade and silence with its thick carpet of brown needles, and where all the shrubs and grasses and flowers have disappeared, except in the open spaces. It was in such a forest and in one of these sunny glades, no doubt, that the knight the little girl tells of in Tennyson:

HOW NATURE RESTORES ABANDONED FARMS

So it is that new lands pass from barren rock to forest, and deep rich soil, and so it is that worn-out soils, the result of reckless farming are finally restored. Hardly any soil is too poor for some kind of a weed. These weeds springing up, die and make soil that better kinds of weeds can use. Later come a few woody plants. In the course of fifteen or twenty years the soil is deep enough to support trees; and in fifty years there is a young forest. At the end of a century fine timber can be cut, the land cleared, and the old place may be as good as new.

But it's a long time to wait! It's a much better plan to take care of the land in the first place.

HIDE AND SEEK IN THE LIBRARY

One of the strangest things about Mr. Lichen, as you will see by looking up the subject in any botany or encyclopÆdia, is that he is really two people—two different plants that have grown into partnership; and that one of the partners supplies water for the firm while the other furnishes the food.

The part of "him" that supplies the food is green, or blue-green, and that is why it is able to do this. This idea that Mr. Lichen is really two people was one of those that was "received with a storm of opposition," but certain lichenologists actually took two different kinds of plants, put them together and made a lichen themselves, as you will see when you look the matter up.

As to just who among these two kinds of plants shall go into partnership—that usually depends on chance and the winds; although in the case of some lichens, the parents determine upon these partnerships, just as they often do in human relations.

If you want to continue this interesting study and become Learned Lichenologists, you will be interested to know that there are a lot of things to be learned, including not only no end of delightful names, such as Endocarpon, Collema, Pertusaria, not to speak of Xanthoria parietina, and loads of others, but there are still things unknown that you may be able some day to find out. For instance, while they know that the two kinds of vegetation that together make a lichen, feed and water each other, it's not known exactly how they do it; although the "Britannica" article has a picture showing the two partners in the very act of going into partnership. The article in the "Americana" shows some striking forms of lichens, and how nature from these very dawnings of life begins to dream of beauty. You will be surprised at the forms shown in the "Americana," they are either so graceful, symmetrical, or picturesque. One of them looks like a very elaborate helmet decoration, or plume of a knight.

This article also tells what an incredible number of species of lichens there are—enough to make quite a good-sized town, if they were all real people.

It also tells why the orange and yellow lichens take to the shady side of the rock; and something about how the lichens get those remarkable decorations and sculpturings, and what the weather has to do with it.

There you will also get a probable explanation of the fact that the manna which the Israelites found on the ground in the morning appeared so suddenly.

In the article in the "International" you will find another picture of how the two partners—the fungus and the alga—make the lichen, and you will learn that Mr. Lichen's name, like Mr. Lichen himself, is centuries old; being the very name given him by the Greeks, and afterward by the Romans.

In the "Country Life Reader" there is an article on the soil that has a very close relationship to the subject of the lichens and their work. It tells, among other things, about the value of humus—decayed leaves, grass, etc.—to the soil. It was the lichens, you know, who started the humus-making business.

The article in the reader on "Planting Time," by L. H. Bailey, expresses the wonder we must all feel when we stop to think about it, at the magic work of the soil in changing a little speck of a seed into a plant.

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