Loe raamatut: «The Romance of Plant Life», lehekülg 7

CHAPTER VII
HIGH MOUNTAINS, ARCTIC SNOWS

The life of a cherry tree – Cherries in March – Flowering of gorse – Chickweed's descendants – Forest fires in Africa – Spring passing from Italy to the frozen North – Life in the Arctic – Dwarfs – Snow-melting soldanellas – Highland Arctic-Alpine plants – Their history – Arctic Britain – Edelweiss – An Alpine garden.

IT is impossible to understand and very difficult to explain the sort of life and consciousness which is enjoyed by plants.

That they do live is obvious; we know instinctively that they enjoy fine weather in summer and gentle showers in spring, but we cannot prove it.

Much of a plant's life is concealed and hidden from us. Even the few explanations which have been given by certain observers are by no means generally accepted.

This is true even as regards the case of the Cherry tree, which has been experimented with, and fought over and argued about by botanists, and yet we only know a very little about its inner life.

When the leaves fall in autumn, next season's buds are already formed and are then about one-eighth of their full size. At this time the tree contains enormous quantities of food-stores, for the whole season's work of the leaves has been accumulating until this moment. During the long winter's "sleep" the tree is by no means at rest. It is arranging and packing up those stores in the safest place and in the most convenient form.

Just as a bear, before it retires to sleep during the winter, takes care to get as fat as possible, so the Cherry turns its starch to fat, and stores it away in the innermost and least exposed parts of the tree, that is in the central wood. As soon as the winter ends, and indeed before it has ended, preparations are beginning for the great moment of the year. For weeks there is a slow, gradual, almost imperceptible growth of the buds, then they develop with a rush, and in six to ten days double or treble their weight. Then comes the supreme moment, for the flower-buds suddenly burst open and the Cherry is in active and vigorous bloom and covered all over with exquisite blossoms. All last year's fats and starches are rapidly used up. Very soon the young leaves are beginning to make sugar and other food, which give some help during the ripening of the fruit.

The flowers are actively at work. One of our usual misconceptions as to the nature of a flower is that it is an emblem of peace, of restful enjoyment, of serene contemplation of its own beauty. That is very far from being the truth. The petals are actively, vigorously working. If one could take the pulse of a petal, which shows the rapidity of its breathing, one would find that it is twice as fast as that of the leaf. The work of changing water into vapour and pouring it out goes on three times as quickly in the petals (as compared with the leaves). Moreover their temperature is higher, and often distinctly above that of the atmosphere.

This feverish activity of the flowers themselves is matched by the hurrying crowds of excited and exhilarated insects which are searching every blossom.

No wonder that the Japanese Prime Minister, in the midst of their great and famous war, invited the whole cabinet to spend an afternoon watching the cherry trees in bloom!

From the blossom of the springtime all through summer and autumn follows one continuous spell of hard work. Day after day an endless stream of food is entering the stem; night after night it is condensed and arranged and repacked, until, when the leaves fall, the period of slow and quiet preparation begins again.

Under certain conditions it is possible for gardeners to modify the life of a cherry, and to make it bloom much earlier, but this is only possible within well-defined limits. It is no use trying to force it to bloom before January. It must have a quiet time after summer. But by beginning in January and by very carefully managing the temperature, it can be made to produce fruit quite early in the year.

The following account is given to show how very carefully gardeners have to work when they upset the ordinary course of Nature's events. The plant is taken into a greenhouse, and the temperature kept as follows: —

Not merely strong, forcing heat, but a little judicious cold, is necessary to get out the flowers and to ripen the fruit.⁴³

Most flowers have very much the same general history as the cherry, but it must not be supposed that they are all alike. The differences are very interesting and curious.

Thus, for example, plants of our common Gorse, furze, or whin may be found in bloom at almost every season of the year. There are at least four seasons when there is that tremendous display of golden blossom which made the great Linnæus fall on his knees and burst into tears. These are about the 22nd March, 24th May, 15th August, and 21st November; yet there are enough odd flowers blooming in almost every month to give some cause for the saying, "The gorse is out of bloom when kissing is out of favour." The last practice, though uncleanly and dangerous, not only on general grounds, but on account of bacterial germs which may be transferred, has been authoritatively condemned in the United States, but it is still more or less popular in other countries at all seasons.

The Chickweed and some other of our annual weeds show a hardy disregard of climate. Its seeds germinate and grow at any time, so that flowers and seeds can be formed whenever there is a spell of favourable weather. Now one chickweed can produce 3000 seeds. Suppose that there are only five generations in the year, which is a very low estimate. Then one seed of chickweed might produce 3000 × 3000 × 3000 × 3000 individuals in one season!

Other plants show much the same tendency. In fine warm autumns a great many annuals bloom a second time. It is on record that forty-four spring species bloomed in one warm November. At the Cape and in other warm climates many of our annuals do not die at the end of autumn, but go on growing. They become perennial.

It is even possible to make a Tree Mignonette by pinching off the flower-buds, though this plant is usually an annual.

In fact plants are not absolutely confined to one rigid scheme, but they can alter and modify their blooming time if they find it convenient to do so. In the Mediterranean some blossom in early spring and others in late autumn, whilst in the dry, hot, and dusty summer very few flower.

In Central Africa during the dry season forest fires are by no means rare. The trees are scattered, and the ground is only covered by dried and withered grasses and sedges. One sees in the distance a rolling cloud of smoke, and soon one comes to a line of flame. It is not dangerous, not even very impressive, for a jump of three feet carries you over the flame and on to a desolate wilderness of black cinders, out of which stand up the scorched trunks and half-burnt branches of gaunt, naked trees. A day or two afterwards, bright blue and white and yellow flowers break out of those scorched branches and also from the ground.

It is difficult to understand why this happens, but certainly it is good for the flowers, which can be seen by insects from a long distance.

But these are unusual cases. Generally the warm breath of spring wakes up the bulbs and buds, and one after another has its moment of flowering.

Spring travels towards the North Pole at an average rate of four miles a day.

A pedestrian visiting Italy in the end of January might follow the spring northwards, and if he wished to accompany it all the way, it would be quite possible to do so without exceeding an ordinary day's march. He would have to reach North Germany by the end of March, Sweden in May, and by the end of June and July would find spring beginning in the desolate Arctic regions.

Of course the presence of mountains would make this tour a little difficult and devious, but still it is quite a possible undertaking. It would be very interesting, for he would be able to watch the cold and frost and chilliness of winter disappearing as the sun's rays thaw out a greater and greater extent of the cold and frozen North.

The life of an Arctic plant is truly set in the midst of many and great dangers.

For 250 days the ground is hard frozen and the temperature never above the freezing-point. About the end of May it begins to rise a little, but the plant has to crowd the whole of its life, its flowers, fruits, and seeds, into the space of two months!

About the 23rd to the 29th June the first flower appears, then follows strong, active growth in uninterrupted sunshine during July and August. The flowers are brilliant in colour and richly produced. The tiny dwarf Arctic plants are covered all over with blue or golden yellow or white blossoms. All is in full activity and luxuriance. Then suddenly, in a night, the icy grasp of winter falls upon them.

Hard-frozen flowers, buds, and ripening fruits remain chilled and incapable of life from the 30th August until the end of May.

Of course, under such conditions, these hardy and vigorous little plants cannot become trees or shrubs. To show the effect of the climate upon them, a few British plants which are also Arctic may be compared.

These wretched little dwarfs seem, however, to have pretty long lives, and, as we have said, deck themselves in the most gaudy colours every summer.

In the Alps of Switzerland and other temperate countries, the flowering season is also a very short one and soon over. It is often not more than six weeks, yet in that short time the rich blue of the Gentian, the Alpine Roses, Soldanellas, Campanulas, and many others make some of these grass slopes high up in the mountains a perfect garden of loveliness.

Sometimes in passing over the snowfields of Switzerland just before spring, one notices the pretty violet flowers of the Soldanella swaying to and fro in the wind above the unmelted snow. One does occasionally see in this country the Snowdrop in the midst of snow, but then it has fallen after the Snowdrop had blossomed.

The Alpine Soldanella flowers whilst the earth is still covered. It begins as soon as the ground below the snow is thawed. Each little developing flower-stalk melts out a grotto in the snow above itself, and so bores, thawing its way up into the air above. It has already been mentioned that, inside a flower, the temperature is often higher than the surrounding air. It is this higher temperature of the flower which thaws a little dome or grotto in the snow above the head of the flower.⁴⁴ When a flock of sheep are covered by a snowdrift, a similar hollow is formed above them by their breath and the high temperature of their bodies: they often seem indeed to be little or none the worse for being buried. The Soldanella melts its way in just the same manner.

In this country we have no such magnificent chain of mountains as the Alps, and yet we find on the Scotch and Welsh mountains quite a number of real alpines.

There are, for instance, such flowers as Sea-pink (Armeria), Sea Plantain (Plantago maritima), Scurvy-grass, and others, which can be found on windy, desolate gullies and corries high up on the Highland hills, and which also occur on the sea-coast, but never between the seashore and the tops of the mountains. You might search every field, every moor, and every riverside throughout the country, but you would not discover those three plants anywhere between the seashore and the summits.

At first sight it seems quite impossible to explain why this should be the case. But all those three plants are found in the Arctic regions, and the explanation is in reality quite simple.

At one time the shores of England and Scotland formed part of the Arctic regions. Ice and snow covered the hills and mountains; huge glaciers occupied the valleys and flowed over the lowlands, plastering the low grounds with clay which they dragged underneath them, and polishing and scratching any exposed rocks.

When the ice began to melt away and left free "berg battered beaches" and "boulder-hatched hills," Lincolnshire and Yorkshire must have been like the Antarctic regions in those days. This is how Dr. Louis Bernacchi describes the Antarctic continent: —

"The scene before us looked inexpressibly desolate… No token of vitality anywhere, nothing to be seen on the steep slopes of the mountains but rock and ice… Gravel and pebbles were heaped up in mounds and ridges. In some places these ridges coalesced so as to form basin-shaped hollows. Bleached remains of thousands of penguins were scattered all over the platform, mostly young birds that had succumbed to the severity of the climate."

Great Britain must have been just as savage and desolate when these hardy little Arctic plants colonized the shingles and rooted themselves amongst the rocks.

They covered not only the seashore, but they probably made a settlement wherever rock or land of any kind was exposed. These original settlers have had three bands of descendants. One band has remained ever since on the seashore of Great Britain; another set gradually travelled northwards. As the ice melted away, leaving the land bare, first in Denmark, then in Norway, and finally in Greenland, this second set followed it, until now we find them far to the northward, populating the Arctic regions of to-day just as they did those of Britain in the Great Ice Age.

The third set of descendants would at first cover all the land and rocks of the lower hills and valleys near the sea; then as the ice and snow melted and exposed the higher mountain sides, they would climb the hills and eventually reach the exposed summits where they are now living. There they find themselves in an impossible, savage sort of climate, in which they alone are able to exist. Violent storms, drenching mist, scorching sunshine (when the rocks become so hot that it is almost impossible to touch them), rainstorms and months of snow and hard frost, cannot kill Scurvy-grass, Seathrift, or Plantain, but there are few other plants which can stand such conditions. Lower down on the flanks of the hills and in the valleys, they have long since been dispossessed of the rich and fertile lands by plants which can grow more rapidly and luxuriantly.

The little Alpine Creeping and Least Willows, for instance, some of which get up to 3980 feet in Breadalbane, are mere dwarfs only a few inches high, and totally different from their allies in the fertile lowlands, which are trees eighty to ninety feet high.

Some of the Alpine plants which also occur in the Arctic regions have not even been able to survive by the seaside in Great Britain. Their nearest allies are in the Norwegian mountains.

It would be impossible even for shrubs to stand the violent winds and snowstorms of these summits. Alpine plants are generally low-growing mats. They are also often clothed all over in cottonwool, such as the Edelweiss. This probably keeps them from losing too much water during the dry season, when the rocks on which they grow are strongly heated by the sunlight.

Yet, like the Arctic plants, they have rich, deep, and brilliant colours.

A queer point is that they have got so accustomed to this stormy and perilous existence that it is extremely difficult to grow them in a garden. Like mountaineers, they dwindle and pine away in the richer soil and softer air of the low grounds.

To make an Alpine garden, rocks and stones must be arranged with pockets and hollows, like natural crevices and basins, between them. Rich leaf-mould must be placed in these hollows. There must be good drainage, and as much sunlight as one can possibly get.

CHAPTER VIII
SCRUB

Famous countries which were covered by it – Trees which are colonizing the desert – Acacia scrub in East Africa, game and lions – Battle between acacia and camels, etc. – Australian half-deserts – Explorers' fate – Queen Hatasu and the first geographical expedition recorded – Frankincense, myrrh, gums, and odorous resins – Manna – Ladanum – Burning bush – Olives, oranges, and perfume farms – Story of roses – Bulgarian attar of roses – How pomade is made – Cutting down of forests and Mohammed.

A scrub or Half-desert does not seem at first sight to be in the least interesting.

But if one remembers such places as Cordoba, Seville, Florence, Genoa, Sicily, Athens, Constantinople, the great cities of Ephesus, Corinth, etc., of St. Paul's Epistles, Persia, Arabia, Palestine, and Carthage, surely the countries which have had such splendid histories deserve a chapter to themselves. What achievements in war, in art, in literature, and in romance are connected with these lands bordering the Mediterranean or fringing the great deserts of Sahara and central Asia!

The animals which belong to such country are also interesting. It is the home of the camel, ass, horse, donkey, not to speak of the giraffe, rhinoceros, gazelle, antelope, zebra, lion, and hyena.

The plants are full of interest too, and some of them are of great importance to man. The Olive, Orange, Fig, Roses, and many perfumes and spice-trees, are natives of scrub. In fact, it is the real centre of all gums, frankincenses, and myrrhs.

As man depends upon plants and animals, and as animals also are dependent on the plant world, it is the climate which really is responsible for everything.

The world of plants is entirely and exactly regulated by the character of the climate. What, then, is the climate of scrub?

Those countries enjoy brilliant sunshine, cloudless skies, and yet there is sufficient rain to permit of irrigation and to prevent the unmitigated desolation of the desert. When, as has happened in many of these famous lands, the forests have been cut down and the aqueducts have been neglected, they become arid, dry, and almost useless. But when carefully and industriously worked, as they were in the days of Greece, Carthage, and Rome, they produce results which will for ever live in the history of the world.

The meaning of such half-desert climates and of the scrub which covers them has been already suggested.

The scrub is trying to occupy the desert.

If one takes the sternwheel steamer at the First Cataract of the Nile and passes southwards, the desolation of black rock and "honey-coloured" sand of the Libyan Desert is at first unbroken. But here and there the thorny trees of the "Seyal". Acacia show the beginnings of a scrub region. Much further to the south, those acacias and others become great forests which extend all along the south of the Sahara Desert and furnish the valuable gums of the Soudan.

If one passes southward through this forest of acacias, it alters in character. The trees become taller, closer together, and climbing plants and undergrowth become more frequent. Still further south, one finds the regular tropical forest which is characteristic of the tropics everywhere.

The most interesting part, which is also the richest in big game, is the intermediate zone between the desert and the acacia forest or scrub.

All sorts of transitions are found. Sometimes there are thickets of thorny bushes. Occasionally scattered clumps of woodland alternate with stretches of grass or what looks like grass. Near the desert one finds pioneer acacias dotted singly here and there; these are the scouts or skirmishers of the army of trees which is trying to occupy and colonize the desert.

This explains why this sort of scrub occurs in so many parts of the world. On the European side of the Mediterranean, the dry climate of Spain, the Riviera, and Greece must no doubt at one time have supported a scrub vegetation. At present it is difficult to tell what this was. There is a sort of scrub called Maqui which covers parts especially of Corsica and other Mediterranean countries. In Greece, also, thorny, woody little bushes are very common.

But these are just what the goats, who are fiends from a vegetable point of view, have been unable to destroy. We cannot tell what sort of country revealed itself to the first Phœnicians when they landed in Southern Spain to traffic with the savage inhabitants, or what met the eyes of Ulysses when he made his great voyage to unknown lands.

But there are places in the world where man has never either kept domestic animals or cultivated the soil. Possibly Spain and Sicily in those early days were not unlike parts of British East Africa, such as the Taru Desert between Mombasa and Kibwezi.

The following may give an idea of how this scrub or desert appeared to me.

Gnarled and twisted acacias of all sorts and sizes, usually with bright white bark and a thin, naked appearance, cover the whole country. Amongst these one finds the curious trees of Euphorbia. In Britain Euphorbias are little green uninteresting weeds, but here some of them are twenty to thirty feet high, with many slender whip-like branches, but no leaves. Others are exactly like Cactus, and take on weird, candelabra-like shapes. Nobody meddles with them for, if the slightest cut is made in the bark, out pours an acrid, white milk which raises painful blisters, and may even cause blindness if a drop touches the eyes.

Almost all the plants are either covered with thorns or protected by resins, gums, or poisonous secretions.

Between the scrubby trees the soil is dotted over by little tufts of grass or sedge, but these are so far apart that the tint of the landscape is that of the soil.

Game is abundant everywhere. Sometimes it is a small bustard or a persistent, raucous guinea-fowl that affords a chance for a good dinner. Occasionally a tiny gazelle, the "paa," with large ears, springs out of the thorns and vanishes down the path. I saw footprints of giraffes, and came across ostriches more than once. I also made a persevering attempt to slay a Clarke's gazelle, an animal with enormous ears and a long thin neck.⁴⁵

These long-necked creatures can see far above the usual short thorny bush, and it is exceeding difficult to get near them. Water probably exists under the stony grit soil, but at present one has to be contented with that found in the stagnant pools at Taru, Maungu, etc., which, if not occupied by the decaying remains of a dead antelope, are, as a rule, drinkable.⁴⁶

These acacias are quite well fitted to live in this dry and arid region. Their roots go down to twenty feet or more, so as to reach the deep-seated water supplies.

Their leaves are generally adapted to resist any injury from the strong glare of the sunshine. The gums, already alluded to, are also very important, for any crack or break in the tree is promptly gummed up, and there is no loss of precious water thereby. This gum will also prevent or discourage burrowing and boring insects from getting in; they would, if they tried to do so, become "flies in amber," like those found in fossil resin. The trees are generally provided with strong spines, which guard them from the many grazing animals which try to devour the succulent leaflets.

The fight between the grazing animal and the plant is, in these scrubs and half-deserts, very severe. In Egypt it is said that the whole flora has been entirely altered by the camel and the donkey.⁴⁷

But in this case the battle is unfair. Man keeps those camels, donkeys, and goats. He provides them with water and protects them from lions, leopards, and snakes. In East Africa man has not yet interfered, and the plants probably get the better of the animals. In such places lions, leopards, and hyenas are common. It will be remembered that a lion not very long ago stormed and took charge of a railway station on the line to Uganda, and was only routed with very heavy loss.

There is also some reason to suppose that the antelopes and other creatures do help the plants in their efforts to colonize the Sahara. Their droppings will very greatly improve the soil, and more vigorous thickets and undergrowth will spring up when the soil is improved in this way. Such a vigorous growth of plants will be better able to resist the long eight or nine months' drought, and so help the wood to develop, until perhaps it is too thick, and the trees are too high, for the antelopes to graze upon them. In this manner the Acacia scrub is slowly and painfully colonizing the desert.

It is not only in Africa that one finds these half-deserts or scrub. There is the Brigalow Scrub in Australia, which has a curious silver-grey shimmering appearance on account of the blue-grey sickle-like leaves of the Brigalow Acacia. The foliage casts no shade, for the leaves are flat and thin, and place themselves edgewise to the light, so that there is no danger of the strong light injuring them. Also in Australia is the Mallee Scrub, covering thousands of square miles between the Murray River and the coast. It consists of bushy Eucalyptus, six to twelve feet high. Its monotonous appearance when seen from a small hill is very striking.⁴⁸ "Below lies an endless sea of yellow-brown bushes: perhaps far away one may observe the blue outline of some solitary hill or granite peak, but otherwise nothing breaks the monotonous dark-brown horizon. Everything is silent and motionless save perhaps where the scrub-hen utters its complaining cry, or when the wind rustles the stiff eucalyptus twigs."⁴⁹

There is a melancholy interest attaching to both the Mallee and Brigalow, for in them lie the bones of many gallant and persevering explorers. Nor is the East African thorn-tree desert without its victims. The missionary, Dr. Chalmers, was lost near Kibwezi in the Taru Desert.

There are a certain number of valuable plants found in these half-deserts or scrubs. Perhaps the earliest geographical expedition of which we have a good account (with illustrations) is that sent by the Egyptian Queen, Hatasu, from Thebes, about three thousand years ago. She built on the Red Sea a fleet of five ships, each able to carry from fifty to seventy people, and sent them to the land of Punt, which was probably Somaliland. The natives lived in round huts built on piles like the ancient lake dwellings. The object of the journey was to obtain incense. No less than thirty-one incense-bushes were dug up with as much earth as possible about their roots, and carried to the ships, where they were placed upright on the deck and covered with an awning to keep off the sun's rays. Whether they did really survive the journey and grow in Egypt is uncertain. Sacks of resin, ebony, cassia, apes, baboons, dogs, leopard-skins, and slaves, as well as gold and silver, were also taken away. The Queen of Punt accompanied them. From her appearance it is not probable that the Queen of Sheba was any relation, although some writers have supposed that Sheba and Punt were the same place.

The whole story is represented in coloured bas-reliefs in the temple at Tel-el-Bahiri, near Thebes.⁵⁰

The incense here alluded to was a very valuable drug in Egypt on account of its use in embalming mummies. Quite a number of gums, resins, and the like, are obtained from Somaliland and similar half-desert countries. The frankincense of the Bible, which may be the incense of Hatasu, is obtained from Olibanum produced by various species of Boswellia. In February and March, cuts are made by the incense gatherers in the bark of the trees. Tears of resin soon appear and become dried by the sun over the wound. The best kinds still come from Saba, in Arabia, where the Romans obtained it in the time of Virgil. Besides Olibanum, frankincense contains Galbanum (Ferula galbaniflua) and Storax (Storax officinale). Equal parts of these were mixed with the horny shield of a certain shell-fish. When the last is burnt, it has a strong pungent odour. The Galbanum is now found in Persia, and Storax in Asia Minor, both half-desert countries. The true Myrrh (Commiphora myrrha) is also found in East Africa and South-west Arabia.

The name is supposed to be derived from Myrrha, the daughter of Cinyras, King of Cyprus, who in consequence of a great crime was banished to Arabia and became the tree which bears her name. The myrrh of the Sacred Oracles was used as incense at least 3700 years ago, and it is mentioned by Moses (Genesis xxxvii. 25).

The sovereign of England used always to present gold, frankincense, and myrrh in the Chapel Royal, London, on the feast of the Epiphany, and, strange though it may appear, the symbolic offering is still made each year by our present king.

Balm of Gilead (Balsamodendron Gileadense) belongs to scrub or half-desert regions. Cleopatra obtained plants from Jericho for her garden at Heliopolis. The Jews used to sell it regularly to the merchants of Tyre.

It is still valuable, for the essence is worth from £2 to £3 per lb.

The opoponax described by Dioscorides belongs to the Orient. It yields a valuable gum resin, which is much used in perfumery (Pastinaca opoponax). It also is obtained by incisions in the bark⁵¹ of the tree.

In fact a very large proportion of these fragrant sweet-smelling substances, Myrrh, Cassia, Bdellium, etc., come from these sunny Eastern lands, which are not exactly deserts but very close to them. Manna, e.g., is obtained from the flowering Ash (Fraxinus ormus) in Sicily by transverse incisions being made in the bark, so that the brownish or yellowish viscid juice exudes and hardens on the wound. Ladanum is a varnish or gluey coating found on the leaves of Cistus creticus, which grows in Crete. In old times the glue was collected from the beards of the goats which had been browsing on the plant. Although this method, no doubt, increased the strength of the perfume, it has been abandoned, and the ladanum is obtained by a "kind of rake with a double row of long leathern straps." The straps take the glue from the leaves. It is used as a perfume in Turkey.

Another very interesting Eastern plant sometimes seen in old-fashioned country gardens in Britain is the "Burning-bush" (Dictamnus fraxinella). Like a great many of these half-desert plants, it is full of an acrid, ethereal, odorous substance. On a calm, hot summer's day, this material exudes from the leaves and surrounds the plant with an invisible vaporous atmosphere. Such an atmosphere probably assists in preventing the water from evaporating or being transpired from the leaves.⁵²