‘I will come,’ said Edgar, with a hearty handshake.—‘Good-night.’
SNOW-BLOSSOM.
Under the above title, Professor Wittrock, in Nordenskjöld’s Studies and Researches in the Far North, has given us a wonderful and exhaustive account of the lowest order of plants—those which have their existence on the surface of the snow and ice, and colour the monotonous white or dirty gray of the everlasting snowfields with the warmest and most lovely rosy red and crimson, vivid green, and soft brown, until it almost appears as if these frigid zones have also their time of spring and blossom.
Late researches go to show that the snow and ice flora is far greater and richer than was at one time supposed. Formerly, people had only heard of ‘red snow’—which Agardh poetically calls ‘snow-blossoms’—and ‘green snow,’ first discovered by the botanist Unger—specimens of which were brought from Spitzbergen by Dr Kjellmann, and from Greenland by Dr Berlin. But a closer examination has discovered in the ‘green snow’ about a dozen different kinds of plants, and these not merely comprising the lowest order, but also including some mosses. The latter, however, were only in their germinating state, looking like the green threads of algæ, and therefore showing a much inferior degree of development to that which they would have if growing on a warmer substratum. The flora of the loose snow, too, is generally far richer than that of the solid ice; already forty different varieties of plants having been found, which number will no doubt be greatly increased by every fresh expedition to the arctic zone. On the solid ice, only ten different kinds have been observed.
There is a great difference between the real ice and snow plants which grow exclusively on the snow-line and those hardened children of the sun which only grow on the snow. The latter all belong to the one-celled microscopic algæ of the lowest order, which increase by partition, possessing no generic character, and generally appearing in large horizontal masses of vegetable matter. They are also distinguished by seldom having the pure green chlorophyll colour of other plants, but instead display shades of red, brown, and sap green, whence they have been named coloured algæ.
Some botanists suppose that the chief and most numerous of all the algæ, the red snow, only represents a lower state of a higher class of algæ which has never attained to full development in the region of perpetual snow; and this supposition is the more remarkable, as the brilliant red granules of this species—about the four-thousandth part of an inch in diameter—probably surpass in reproductive powers every other plant. They cover enormous tracts of snow in such dense masses that it sometimes appears as if the snow was coloured blood-red to the depth of several feet. Ever since it was first found, red snow has greatly exercised the minds of the learned. It is often mentioned in old writings, though whether the red snow referred to took its colour from the red algæ or from the meteor-dust which contains iron, is not certain. But there is no doubt that it was the real red-snow algæ which De Saussure found in his Alpine expeditions. He mentions this phenomenon several times in 1760, and states that he had found the most beautiful species on Mont St Bernard, but had thought it must be pollen, wafted thither by the wind, although he knew of no plant that had that kind of red pollen.
The knowledge that the red snow of the polar regions and mountains owes its colour to a living plant, only dates from the year 1818, when Ross and Parry made their celebrated polar expedition, and Ross discovered the ‘crimson cliffs’ of the coast of Greenland, six hundred feet above the level of the sea. Here the red snow coloured the rocky walls of Baffin’s Bay a rich glowing crimson, reaching in some parts to a depth of nine or ten feet, and close to Cape York extending over a distance of eight nautical miles. Various were the surmises and conjectures as to the origin and nature of the phenomenon. Bauer was the first to examine it under a microscope, and he fancied the organic red granules represented a species of fungus. The same year, Charpentier, the great Alpine explorer, started the idea that the red appearance was caused by some meteoric matter, which, falling from the sky, spread over the immense tracts of snow. Hooker was the first who recognised the true nature of this new plant, and compared it to the red slime algæ which are found floating in blood-red masses in water or damp places; while Wrangel declared the granules had apparently no organic substratum, and they must therefore be of the lichen tribe, suggesting also that the germs were generated by the electricity in the air, for he had once seen a rock split in two by lightning, the sides of which were thickly covered with a red dust similar in nature to the ‘red snow.’ Two more botanists agreed that the red granules were ‘red powder that had become organic matter in the oxidised snow;’ the stern hard rock as it decayed had defied death, and come to life again in a new form. It remained for Agardh to put an end to these various fancies by proving the undoubted algal nature of the plant, and to give it, besides, its poetical name of ‘snow-blossom,’ the scientific one of crimson primitive snow-germ (Protococcus Kermesina nivalis). In 1838, Ehrenberg watched the development of this new species by sowing some specimens he had brought with him from the Swiss Alps, on snow, and noting how they developed first into green and then into red granules, joined together like a chain; he called it snow granulæ (Sphærella nivalis), which name it still bears.
Even now, the wild theories about the red snow were not yet ended. Seeing that the young spores of the algæ moved incessantly backwards and forwards in the water, the idea arose that they were animalcula, and ‘red snow’ only the lowest form of animal life. By degrees, however, it came to be an accepted fact that this voluntary motion does not belong exclusively to animal life, and that the young spores of the lower plants, although they move freely about in the water, and are plentifully provided with fine hair-like threads like the real infusoria, still remain plants, and never turn into animals. And thus the plant-nature of the ‘snow-blossom’ was finally settled.
The red-snow alga found on the Alps, Pyrenees, and Carpathians, and also on the summits of the North American mountains as far down as California, is not, however, such a determined enemy to heat as its having its home in the ice-region would imply. In the arctic circle, as well as on our own mountains of perpetual snow, especially on Monte Rosa, the red snow is seen in summer like a light rose-coloured film, which gradually deepens in colour, particularly in the track of human footsteps, till at length it turns almost black. In this state, however, it is not a rotten mass, but consists principally of carefully capsuled ‘quiescent spores,’ in which state these microscopic atoms pass the winter, bearing in this form the greatest extremes of temperature. Some have been exposed to a dry heat of a hundred degrees, and were found still to retain life-bearing properties; while others, again, were exposed with impunity to the greatest cold known in science. This proves that the reproductive organs in a capsuled state can hear vast extremes of temperature without injury; a significant fact, in which lies the secret of the indestructibility of those germs which are recognised as promoters of so many diseases.
Time, too, that great destroyer of most things, seems to pass harmlessly over this capsuled life. If the spores find no favourable outlet for their development, they do not die, no matter how long a time they may remain thus; and so the dried remains of red snow brought home from various polar expeditions have, even after the lapse of several years, fructified. During the uninterrupted light of the arctic summers, the ‘snow-blossom’ develops itself so rapidly, that at last it covers vast and endless tracts of snow. Although the sun does not rise very high above the horizon even at midsummer, yet, owing to the great clearness and dryness of the atmosphere in those high regions, it has a considerable degree of warmth at noon, and Nordenskjöld observed that one day in July, at mid-day, the temperature just above the snow was between twenty-five and thirty degrees centigrade. But it must not be supposed that the red alga vegetates in the pure snow; this would not be possible, as, according to chemical analysis, its body contains numerous mineral substances. The outer skin or membrane, particularly, in which the granulæ are stored seems to hold a quantity of silicon; but chalk, iron, and other mineral substances peculiar to the vegetable world, are also not found wanting in the ashes of the red snow. In fact, the upper surface of the snow and ice always shows, whenever it has lain long enough, a thin coating of inorganic dust, which brings to the snow alga the mineral constituent parts it requires.