The question of the origin of the Alpine flora is a subject upon which botanists are by no means completely agreed at the present time. A large number of the thousand different plants that are found in the high Alps reappear in distant mountains and the Arctic regions, though absent in the intervening country. Thus the late John Ball calculated that 17 per cent. of the Alpine species were met with in the Arctic regions, and 25 per cent. in the Altai Mountains of Northern Asia. That this is not due to the conveyance of seeds from place to place by the agency of wind or birds is shown by the fact that the resemblance of the plants of different mountain chains to one another is in no way proportional to their geographical proximity, even when their climate is similar. The true explanation is probably to be sought in the Glacial Period, in which the greater part of Europe was covered by ice, so that the climate of the plains was very similar to that of the high Alps and Arctic regions at the present time. At this period the flora of the extreme north was able to mingle with that of the mountain regions. When the climate of the intervening districts became once more less severe, the competition with the present lowland flora became so keen that the Alpine-Arctic plants retreated to high altitudes or the far north. It may be that the high mountain regions have formed centres for the evolution of new species, as Mr John Ball believed, but there is but little direct evidence for this view.
Nearly every visitor to Switzerland who regards its rich flora in any way worthy of notice is desirous to obtain some permanent record of the pleasing impressions obtained. Either the flowers are pressed, or the plants are pulled up with more or less of their roots to be planted in some garden at home, or, as the author would suggest is by far the best method, photographs of the plants are taken. May we here, first of all, protest against the wholesale destruction of Alpine plants that goes on every year by careless visitors. Where a few flowers are required for study or to be preserved by pressing, they may, by all means, be picked. There seems no reason also why a few of the more common or abundant plants should not be dug up with their roots, carefully packed, and taken home, although the Swiss authorities do not permit even this, but it is disgraceful that large nosegays of choice flowers should be gathered for the mere pleasure of watching them wither in the hand, and then thrown away. The Swiss natives, unhappily, set us a very bad example in this respect; but it is fortunate that the Edelweiss and Alpenrose are the only flowers that they at all extensively attack. Many of the more frequented tourist routes have become almost bare of any but the commonest flowers. One has only to ascend to some peak or glacier by two paths, one that is well-trodden, and a second but little used, to see how complete this destruction of wild flowers has been.
Excellent little presses for preserving plants and flowers can be bought in Switzerland. They take up no more room in one’s bag than a Baedeker or Bradshaw’s Guide, and do the work much more efficiently. Their only disadvantage is that they are generally too small to display any but the tiniest plants completely, and it is really wiser to take out from England a couple of boards with straps and a good supply of blotting paper. The special paper sold for pressing plants is much to be preferred to ordinary white or pink blotting-paper, as the plants tend to stick to it much less. A fair amount will be required, as the plants need frequent changing and the paper must be dried. Specimens should be carefully set out by pressing on them with the finger till they take up the required positions, and stored when dry in some exercise book or between sheets of paper.
The cultivation of Alpine plants in our gardens at home is by no means as easy as might at first be supposed. The climate and conditions of life in Peckham are very different to those at the summit of Pilatus, and unless the thing is done carefully and thoroughly it had better not be attempted at all. The chief difficulty in growing Alpine plants in our climate is not the cold but the excessive moisture of winter, which tends to rot their roots, and from which they are protected in their native home by their snowy covering. Our object should be to reproduce, as far as possible, in our gardens the conditions under which the plants grow in the high Alps. For the rockery a porous stone will be required, such as limestone or sandstone, and it is essential to select a kind that does not crumble with the frost. The partially fused masses of brick, which can be obtained very cheaply as a waste product from brick kilns, when washed over with a mixture of cement and sand do very well. The rocks and stones must be so laid that every bed or pocket in which the plants are to grow is thoroughly well drained, for nothing is so destructive to them as water-logging of the soil. Plants that grow in the clefts of rocks should be planted in a sloping position, as water is then less liable to collect in the rosettes of leaves. Those that grow in cool, moist, spongy soil are best planted in a mixture of peat moss and earth. It is also important to notice whether the plant which is being cultivated was previously growing on limestone or granitic soil, for it is easy to add a little chalk to the earth if this is required. In planting out one has to be careful not to curl up the roots, and it is wise to sprinkle the plant with water two or three times a day for the first week or so. Alpine plants should never be manured. It should be remembered that mountain plants grow slowly, and though very many species can be successfully cultivated, the Houseleeks and Saxifrages are likely to give the best results with a minimum of trouble.
It is impossible in such a book as this to give more than a few general suggestions as to the photography of Alpine plants. One of the chief difficulties with which one has to contend is the wind. When the plant is photographed anywhere near its natural size the smallest stop has to be used to obtain depth of focus, and this greatly increases the duration of the exposure. Many of the colour photographs herein reproduced were given as long as five or ten minutes. When the wind is intermittent it is quite safe to give repeated exposures of a few seconds at a time, being careful in removing and replacing the cap not to shake the camera, for the plant is sure to return to exactly the same position after being blown to and fro by the wind. Where tall plants are being taken it is wisest to select a time in the early morning or near sunset, for though the intensity of light is diminished at these times, there is usually but little wind. The writer has found a strip of white calico, some 12 or 15 inches wide, with long knitting needles sewn on to it at intervals, of great value as a wind screen in plant photography. The knitting needles can be pushed into the ground, and the plant surrounded on three sides or completely by such a screen, and thus very largely shaded from the wind. With a little care the screen does not appear in the photograph, and it is easily rolled up and carried from place to place. For near objects the intensity of light in the Alps is only slightly greater than that in England at the same time of day, but it is always wiser to make use of an exposure meter if the best results are desired. By the use of the swing back any plane surface, whatever be its inclination to the vertical, can be easily focussed. This will be found of especial value where a blurred background is desired, and the slight distortion thus obtained, which is so noticeable in architectural subjects, is quite negligible in the case of plant portraits. The deep shadows that are produced when flowers are photographed in bright sunlight are generally best avoided.
SUMMER FLOWERS OF THE HIGH ALPS
HERE FOLLOW COLOURED PLATES AND DESCRIPTIONS OF 39 SWISS PLANTS, WITH THEIR NAMES IN LATIN, ENGLISH, FRENCH, AND GERMAN