Читать книгу: «The Romance of Plant Life», страница 14

If it were the St. John's River, we might see that extraordinary Florida Hyacinth which has swollen, gouty-looking leaf-stalks, and grows with such extraordinary rapidity that it covers the whole surface of rivers, choking the paddle-wheels of steamers and destroying the trade in timber, for no logs can be floated down when it covers the water. Its rosettes float on the surface, and are very interesting to examine. If you upset one or turn it upside down in the water, the "buoys" or swollen stalks act as a self-righting arrangement, and it slowly returns to its proper position.

But in most rivers, one is certain to come across backwaters where it is impossible to force a boat through on account of the reeds and other marsh-plants.

There are places on the Danube where hundreds of square miles are occupied by waving masses of the feathery-plumed Phragmites, almost to the exclusion of any other sort of vegetation. Giant specimens of it eighteen feet high have been observed.

The same reed occurs in North and South America and far up towards the Arctic regions. At first sight it seems as if this was a mistake of Nature; why should so much of the surface be occupied by this useless vegetable? But it is necessary to say a little more about its habits and its object in life.

The most interesting and curious point is the way in which it grows in dense thickets; the main stem is really horizontal and below the water, but it gives off a number of upright stalks. Now every flood will carry in amongst the stalks quantities of silt and rubbish. Those upright stems will sift the water: all sorts of floating material, sand, silt, dead leaves, fruit, etc., are left amongst them. So that such a marsh or bed of Phragmites is gradually, flood by flood, collecting the deposits of mud, and the bed becomes every year more shallow. At the edge of the marsh there is scarcely any water visible, and grasses and other plants are beginning to grow between the Phragmites stems. Eventually these latter are choked out, and a marshy alluvial flat occupies the site of the old reed-bed.

So that the work of Phragmites is of the greatest possible importance: it has to form those fertile alluvial flats which are found along the course of every great river, and which are by far the most valuable lands in the whole world.

Look, for instance, at the population of Belgium, Holland, and Lower Germany, and notice how dense it is upon the alluvial flats where the Meuse, Rhine, and other rivers approach the sea. It is just the same in Britain. London lies on the great alluvial flats of the Thames, Glasgow on the Clyde, Liverpool on the Mersey. In China it is the Yang-tze-kiang valley (especially near its mouth); in India, the Ganges, of lower Bengal, and in the Argentine the La Plata River, which show the greatest accumulations of humanity. In every case it is the rich flat alluvium, which is exceedingly fertile when drained and cultivated, that has originally attracted so many people.

Lower Egypt is the gift of the Nile, but it is not so much the Nile as these neglected water plants which made the rich lucerne, cotton, and food crops of Lower Egypt possible. Amongst the Egyptian Reeds one especially is of great importance. The Papyrus antiquorum, ten feet high, has much the same habit as our Phragmites and other water plants. It forms dense, almost impassable thickets, sometimes completely occupying and choking a small valley, or leaving only a passage, often changing and half choked, through a larger one. This, with other plants, makes the "sudd" of the Nile, which is one enormous accumulation of marsh plants and reeds floating on the water and covering a length of over 500 miles.

It was from the Papyrus that the ancient Egyptians made their paper. The stems are six to seven inches in diameter. "The pith of the larger flowering stems … cut into thin strips, united together by narrowly overlapping margins, and then crossed under pressure by a similar arrangement of strips at right angles, constitutes the Papyrus of antiquity."

These great marshes and reed-beds are full of interest to naturalists. The Fens of Lincolnshire and the Norfolk Broads show the way in which water plants keep hold of the worn and travelled rubbish of the hills, and prevent most of it from becoming useless, barren sea-sands. These places, however, like the sudd of the Nile, and the Roman "Campagna," have an evil reputation so far as climate is concerned. This used to be the case even in lower Chelsea, in London (where snipe were shot not so very long ago). It is as if Nature had desired to do her own work in peace and without being disturbed, for fever, ague, mosquitoes, and malaria are very common. Yet a certain number of people always live in such places. In France, e.g., the leeches in the great marshes near the Landes form a source of riches. Such reeds also are or were the home of the hippopotamus, crocodile, and other extraordinary animals. The extinct British hippopotamus no doubt found in the Chelsea or other marshes a home as congenial to its tastes as is the sudd of Egypt to its living descendants or allies. In other places the enormous quantities of water birds, myriads of ducks, geese, swans, regiments of flamingoes, snipe, and the like, have called into existence peculiar kinds of industry in fowling and netting that are not without importance. The decoys in the Fens yield hundreds of birds for the London market, and the duck-punts with their huge guns also bring in quantities of wild fowl.

But all this industry is very trifling compared with that of Phragmites and its associates, who have strained from the water of the Thames most of the ground on which London now stands.

CHAPTER XVII
ON GRASSLANDS

Where is peace? – Troubles of the grass – Roadsides – Glaciers in Switzerland – Strength and gracefulness of grasses – Rainstorms – Dangers of drought and of swamping – Artificial fields – Farmer's abstruse calculations – Grass mixtures – Tennis lawns – The invasion of forest – Natural grass – Prairie of the United States, Red Indian, Cowboy – Pampas and Gaucho – Thistles and tall stories – South Africa and Boers – Hunting of the Tartars – An unfortunate Chinese princess – Australian shepherds.

WHERE should one seek for peace on earth? The ideal chosen for one well-known picture is a grassy down "close clipt by nibbling sheep," such as the fresh green turf of the South Downs.

Others might prefer the "Constable country," near perhaps the famous "Valley Farm" of which the picture now hangs in the National Gallery, and especially in early spring. At any rate, once seen, one remembers for ever afterwards those glossy-coated, well-fed, leisurely cows grazing hock-deep in rich meadows full of bright flowers and graceful grasses, through which there winds a very lazy river bordered by trim pollarded willows.

The charm of the South Downs and of Constable's meadows depends upon their peaceful quiet, and the absence of any sign of the handiwork of disturbing man.

But such meadows are entirely artificial. They could no more exist in nature than a coal-mine, if it were not for man's help. Moreover, they are in a state of perpetual war! No plant within them experiences the blessings of peace from the time it germinates until the day that it dies.

Each plant is fighting with its neighbours for light, for air, for water, and for salts in the soil, and it is also trying to protect itself against grazing animals, against the vole which gnaws its roots, and against the insects and caterpillars which try to devour its buds.

Besides its own private and individual troubles, it is but one of a whole company or army of plants which, like a cooperative society, occupy the field.

Other societies, such as peat-moss, thickets, and woods, try to drive out the grasses and cover that particular place in its stead. The Grassland companions are also always trying to take up new ground, and to cover over any which is not strongly held by other plants.

A road, for instance, is always being attacked by the grassland near it. It is sure to have a distinct border of Rat's Tail Plantain, Dandelion, Creeping Buttercup, and Yellow Clovers. These are the advanced guard of the grassland. However heavily you tread upon these plants, you will do them no injury whatever, for they are specially designed to resist heavy weights. But, if the road were only left alone, these bordering plants would be very soon choked out. The ordinary buttercup would replace the creeping species, and white or red clovers take the place of the little yellow ones, whilst grasses would very soon spring up all over it.

But of course the roadman comes and scrapes off all the new growth of colonizing grasses, etc. Then the plantains, dandelions, and yellow clovers patiently begin their work again.

In Switzerland, in those valleys in which the glaciers are melting away, leaving stretches of bare mud, scratched stones, and polished rock, plants immediately begin to settle there. A Swiss botanist watched the process during five or six years, and describes how first the yellow Saxifrage (S. aizoides) establishes itself. Next season Coltsfoot, willow-herb, Oxyria, and two grasses had planted themselves. During the third season another grass came in. By the fourth season, Fescues and yarrow had appeared, and by the fifth season, five grasses, clovers, and yarrow had formed a regular grassland upon the new untouched soil.¹⁰⁵

In such cases, Nature, who abhors bare ground, is endeavouring to clothe it with useful vegetation.

The fights which are going on are of the most ruthless character. Many weeds are said to produce some 30,000 seeds in one year, and every plant which grows in a meadow is scattering thousands of seeds. But of course the number of plants remains much the same, so that 29,999 seeds are wasted (or the seedlings choked out) for every one that grows up!

It is probably because of this perpetual warfare that the growth of the grasses is so vigorous, and their whole structure so perfectly adapted. If you watch a flowering grass, you are sure to notice how narrow is its stem compared with the height. A factory chimney only fifty-eight feet high requires to be at least four feet broad at the base, yet a ryeplant 1500 millimetres high may be only three millimetres broad near the root. Man's handiwork, the chimney, is in height seventeen times its diameter, but the height of the grass is 500 times its diameter.

The neatness of design, the graceful curves and perfect balance in the little flowering branches at the top of a haulm, is always worth looking at, and particularly in the early morning when it is beset with sparkling drops of dew.

It is all wiry, bending and swaying to the wind so as to produce those waves which roll across a hay-field, and on which the shimmering light is reflected and changes colour. The fight for light and air, the struggle to get their heads up above their competitors, produces all this exquisite mechanism.

It is true that a heavy rainstorm may beat the stems flat down to the ground, but, as soon as the weather becomes dry again these same stems will raise themselves up and become upright; they have a special sensitiveness and a special kind of growth which enables them to do this.

There are two special dangers which all such artificial meadows have to withstand. Let us see what will happen if such a meadow begins to dry up through a sinking of the level of the water below the soil.

Each grass has its own special favourite amount of moisture. It likes to have its water at just one particular depth below the surface. Unfortunately there are not nearly enough sympathetic and careful observations of the preferences of each individual grass. A Danish author has worked out the facts in certain localities (Geest). Suppose first that the water-level of the wells, etc., is 6-1/2 to 9-3/4 feet below the surface. This suits the Meadow Poa grass (Poa pratensis) exactly. It will grow luxuriantly and flourish. Now suppose the weather is very wet, so that the water rises in the wells till they are three to four feet deep. The Roughish Poa (P. trivialis) prefers this moister soil, and it will grow so vigorously that it will kill out the other kind. If it is a season of very heavy floods, or if the drains become choked so that the water rises to within fourteen to twenty-five inches of the surface, then the tufted Aira (Deschampsia caespitosa) will kill out the other kinds and flourish abundantly. But if the water rises higher than this the marsh series comes in (see Chap. XVI.).

So that the thirsty grasses of the meadow are helped or hindered in their fight for life by changes in the water away down in the soil below their roots.

Even in Great Britain one can see distinct differences in very dry and very wet summers, but all these pastures, meadowlands, and hay-fields are, as we have already mentioned, as much due to man's forethought and industry as a factory or coal-mine.

It is very difficult to realize this. The best way is to go to the National, or any other good picture-gallery, and look carefully at any landscapes painted before the year 1805. You will scarcely believe that the country as painted can be the land we know. Where is the "awful orderliness" of England? Where are the trim hedges? Where are the tidy roadsides and beautifully embanked rivers that we see to-day?

As a matter of fact, until the great Macadam made good roads and the great Telford and other engineers built stone bridges, it was impossible to rely on getting about with carts and carriages. Gentlemen's coaches and wagons used to be literally stuck in the mud! Horses were drowned at fords, or died in their struggles to pull very light loads through mud which nearly reached the axles of the wheels (see Chap. XI.).

Besides the change due to roads, fences, drains, and farm buildings, the very grasses themselves are growing unnaturally. The farmer has selected and sown what he thinks best.

He is obliged to do so, because grasses vary so much. Some of them shoot up quickly and die after the first year. Others live for two years, whilst a great many bide their time, developing very slowly, and not reaching their full growth until the fourth or fifth year.

Some are tall and vigorous, others are short; some flower early in the season, and others very late. Many send out quantities of suckers or runners at the base, so that they form a dense, intricate turf – a mass of stems and roots thickly covering the ground.

A farmer wants his pasture to begin early and to continue late; he must have a good first year's crop, and it must remain good for years afterwards. So that his calculations as regards the proportions of the different grass seeds which he requires are of the most abstruse character.

To sow such "permanent pasture," prepared by blending together grasses and clovers with an eye to all the above necessities, there will be needed some seven million seeds for every acre.

The art consists in coaxing the good, lasting, nutritious ones to make both tall hay, rich aftermath, and a close, thick turf below, and, until these are ready, to use the annual and biennial grasses.

Such beautifully shaven, green, soft turf as one sees in the lawns of cathedrals or the "quads" at Oxford and Cambridge has been most carefully and regularly watered, rolled, and mown for hundreds of years. It is not easy to keep even a tennis-lawn in good condition. Little tufts of daisies appear. Their leaves lie so flat that they escape the teeth of the mower, and they are not so liable to be injured by tennis-shoes as the tiny upright grass-shoots which are trying to spring up everywhere. The Plantain is even worse, for it is specially built to stand heavy weights, and it has several roots which divide and branch like the prongs which fix teeth in the jaw, so that it is very difficult to howk it out.

Thus our grasslands in Britain are unnatural and artificial productions. If the field drains are choked, moss or fog and rushes appear. Still more interesting, however, is what happens if the farmer is not careful to destroy the taller weeds, such as Dock, Ragweed, Cow Parsnip, Thistles, and the like. If you walk over a grass-field in early spring, you are sure to see some of these pests. At this stage they have a very humble, weak, and innocent appearance: they are quite small rosettes or tufts. Yet they are crowded with leaves, which are hard at work busily manufacturing food material. Soon they begin to shoot up. Their leaves overreach all the neighbouring grasses. Their roots spread in every direction, taking what ought to go to the "good green herb intended for the service of man." They finally accomplish their wickedness by producing thousands of seeds, which are scattered broadcast over the fields.

By this time the farmer sees what is going on, and endeavours to cut them down; but it is a long, slow, and laborious proceeding. One year's seeding means seven years' weeding.

Yet these tall Thistles and Ragweeds are only the first stage of a very interesting invasion. Look around the field corners, on railway-banks, or in old quarries, where man has left things alone. You will see these same tall herbs (the Ragweed, etc.), but you are sure to find a place where they are being suppressed by Rasps, Briers, and Brambles. These are taller, stronger, and more vigorous than the herbs, and they also last longer, for their leaves are still at work in November. This is the second stage of the invasion. But if the place has been long neglected, Hawthorns and Rowans, Birch and Ash will be found growing up. These last show what is happening.

A wood is trying to grow up on the grassland. If left alone, an oak or beech forest would, after many years, spread over all our grass pastures and hay-fields. These tall herbs are the pioneers, and the briers and brambles are its advanced guard.

As a matter of fact, by far the greatest part of our agricultural land was a forest, but it has been cut down, drained, dug, weeded, hedged, and "huzzed and maazed" with agricultural implements and more or less scientifically selected manures, until it is made to yield good beef, excellent mutton, and almost the largest crops per acre in the world.

Natural grasslands exist, however, in every continent.

The great Steppes of Southern Russia and the pastures that extend far to the eastward even to the very borders of China, the Prairies of North America, the Pampas of Argentina, the great sheep-farms of Australia, and a large proportion of South Africa, consist of wide, treeless, grassy plains, where forests only occur along the banks of rivers, in narrow hill-valleys, or upon mountains of considerable altitude. Upon these great plateaux or undulating hills the rainfall, though it is but small in amount, is equally distributed, so that there is no lengthy and arid dry season. Take the American Prairie, for instance. These valuable lands, once the home of unnumbered bison and hordes of antelopes, lie between the ancient forests of the eastern states and the half-deserts and true salt deserts of the extreme west. Rivers, accompanied in their windings by riverside forests, are found (especially in the east). The real prairie has a blackish, loamy soil, covered sometimes by the rich Buffalo or Mesquite grass, which forms a short, velvety covering, not exactly a turf such as we find in England, but still true grassland. It is only green in early spring.

From the spring onwards until the end of summer there is an endless succession of flowers. The first spring blossoms appear in April; great stretches are covered with Pentstemons, Cypripediums, and many others in May and June; then follow tall, herbaceous Phloxes, Lilies, and Asclepiads, but perhaps the most characteristic flora blossoms still later on, when every one "wants to be in Kansas when the Sunflowers bloom." Over these prairies used to travel the great wagons or "prairie schooners." The cowboy, who almost lives on horseback, watches over great herds of cattle and troops of half-wild horses. Yet his life is, or used to be, almost as free, comfortless, and uncivilized as that of the buffalo-hunting Indian who preceded him. One must not forget to mention the prairie-dog – able to utilize the abundant grass, and diving into a safe refuge underground when threatened by the wolves or other carnivorous creatures, which, of course, multiplied exceedingly, thanks to the jack-hare, antelopes, and bisons.

The Pampas in South America is a similar grassland. On the east it stops at the woodlands along the great Plate River, but on the west it becomes gradually more dry and arid, until long before the Andes are reached it is too dry even to carry sheep, and can only be described as a half-desert.

"It is a boundless sea of grasses fading into the distant horizon, which can only be distinguished when the sun is rising or setting." Yet amongst the grasses are hundreds of flowers, and, a fact which is very remarkable, many of them, such as Fennel, Artichoke, Milk Thistle, Burdock, Rye Grass, etc., are European plants which have dispossessed the natives over miles of country, exactly as the gaucho has driven away or exterminated the Indians who lived there. It is covered by tufts of grass betwixt which appears the rich alluvial earth, yet in good years it may become almost a perfect grass floor. "The colour changes greatly, for in spring when the old grass is burnt off, it is coal-black, which changes to a bright blue-green as soon as the young leaves appear; later on it becomes brownish green, which again changes when the silver-white flowers come out to the appearance of a rolling, waving sea of shining silver."

Here would be the place to mention how an army encamped upon the Pampas finds itself next morning imprisoned and doomed to perish miserably in a forest of giant thistles which has sprung up during the night. There is no doubt that thistles and other weeds are very tall in both South and North America. Fennels are ten to twelve feet high, and even little Chenopodiums (such as in England may reach eighteen inches), become in South America seven to eight feet high, but the tallness of some of the stories is more remarkable even than that of the plants!

Over the Pampas used to roam thousands of guanacos (a creature of the most unlovely type, which resembles both a camel, a mule, a deer, and a horse); here also were Darwin's ostriches (Rhea Darwinii) and other game, which were caught by the lasso and by the peculiar "bolas" of the Indians. They used to surround the herds and then massacre them by hundreds. The "tuco tuco" also, which is a burrowing rodent with habits very like those of the prairie dog, finds plenty of sustenance in the abundant grasses. Upon them subsist pumas, foxes, and other carnivores.

We have said that the Pampas gradually changes from being very fertile on the east to being almost a desert on the west. Here is the place to mention a very interesting, if not romantic, fact. The guanaco does not travel hundreds of miles in order to die in one particular spot as soon as it feels ill, but it does resort especially to certain spots. There the grass is often a bright, fresh green, for it is plentifully manured, and consequently the guanaco helps to encourage the good grasses to occupy a half-desert. On the eastern side of the Pampas great changes are beginning to appear. The owners of the great camps, haciendas or cattle-ranches let off small parts of their land to Italian "colonists." These people grow crops of Indian corn, and when that has been reaped, the valuable Alfalfa or Lucerne is sown down. This forms the most exquisite and valuable pasture, and consequently far more Shorthorn and Durham cattle can be maintained.

There are in South Africa enormous grassy plains, where once springbok and other game used to exist in enormous herds (Wangeman records having seen a herd of antelope four miles long), in spite of lions and other beasts of prey, and in spite also of the Boer, who was as much a horseman as the gaucho or Red Indian. The great buck wagons of South Africa were almost as much the real homes of the Boers as the two-roomed huts which make up his "farms."

The great Steppes of Russia and Siberia are also grasslands. "As seen from a distance hills covered by the Stipa grass resemble sand-hills, but, when nearer at hand, the sand-grey colour changes into a silvery white, and these ever-moving grasses remind one of the waves of the ocean and, in spite of their monotony, leave a pleasant impression."¹⁰⁶

Tulips, Hyacinths, Veronicas, Periwinkles, Scotch Thistles, Euphorbias, Wormwoods, and other of our common plants or their near cousins, make up most of the flora of the Steppes. Yet there are hundreds of others, for it is a vegetation very rich in species.

If one reads in Gibbon's stately language of the mode of life of the Huns, the Scythians, and those other barbarians who, originating in these huge grasslands, occasionally overflowed and overwhelmed the civilization of declining Rome, the resemblance to Red Indians, Pampas Indians, cowboys, gauchos, and Boers is not a little striking.

Read, for instance, the magnificent account of the great hunting matches of the Tartar princes. "A circle is drawn of many miles in circumference, to encompass the game of an extensive district; and the troops that form the circle regularly advance towards a common centre, where the animals, surrounded on every side, are abandoned to the darts of the hunters." Both the Red Indians of the Prairie and the savages of the Pampas used to surround and destroy the game in exactly the same way.

The unfortunate Chinese princess given over for political advantages to a prince of the Huns, "laments that she had been condemned by her parents to a distant exile, under a barbarian husband, and complains that sour milk was her only drink, raw flesh her only food, a tent her only palace." This describes exactly the ordinary life and home of the Huns. "The Scythians of every age have been celebrated as bold and skilful riders; and constant practice had seated them so firmly on horseback, that they were supposed by strangers to perform the ordinary duties of civil life – to eat, to drink, and even to sleep – without dismounting from their steeds." Red Indians of Pampas and Prairie, cowboy and gaucho, lived exactly in the same way.

In those pages of Gibbon which treat of the Huns, Scythians, and other hordes, one recognizes sometimes the wagon of the Boers; sometimes a migration of the East African Masai; then perhaps it is a weapon that is really the lasso, or a disposition and character exactly paralleled by the Crows and Blackfeet. Even the great grass plains of Australia, where the kangaroo, the wallaby, and the dingo have been replaced by the sheep and the "Waler" horse, one finds, in the shepherd and squatter, traits that remind one of the gaucho or the cowboy.

Nor is this in the least extraordinary, for when a scanty rainfall produces those great limitless rolling seas of grass, Nature provides first large herbivorous animals to eat it down as well as carnivorous beasts to keep their numbers in control, until such time as a race of horsemen appears, whose domestic cattle replace the bisons, guanacos, kangaroos, and antelopes, and so assist in replenishing and subduing the earth.