The Parents' Review
A Monthly Magazine of Home-Training and Culture
"Education is an atmosphere, a discipline, a life."
by Sophia Armitt
"In a drear-nighted December
I.--WHAT DOES A PLANT DO DURING WINTER?
There is much more in this subject than is altogether apparent at first. To the words used as a question one is inclined to answer simply by the single syllable, "rest"; but no one word, as no one fact, is final; there is ever the further question, what is rest? and to describe a state is perhaps less easy than to define an action. Plants not only rest, or go through the quiescent period we call rest, but they are making preparations for that rest all through their summer's activity. They could not, perhaps, fall into this state of dormant activity without having gone through the necessary preparation. The moralist might find an opening here, and preach to the too active minds of the present day, that they will not be able to rest either when their working time is over, if they have been working too fast and not taking the required time for the preparation for the state of rest which all through nature seems the sequence to activity.
When the activity of plant life is checked or arrested by the cold of winter, the buds upon some plants, such as the ivy, maintain their form because their further development is discontinued, until, with the warmth of spring, they begin to grow again. But the majority of trees and shrubs prepare for themselves peculiarly organised winter buds, which develop at the ends or the sides of the branches as special organs. When these winter buds are about to be formed, the production of leaves suddenly ceases and a number of leaf rudiments assume the form of scales, closely surrounding the nascent twig and glued together firmly with sticky substances--resin or balsam. Often it is the side shoots of trees, which, as they originate, take on the form of winter buds, and so commence their life with the production of scales in place of leaves. In many trees we find in the autumn, if we take the trouble to open the large winter buds--such as the horse-chestnut, the oak, the beech, or the buds of the fruit trees--already not only the young shoot which is to develop next summer, but a branch system with flower-buds and leaves fringed with delicate hairs, all fully formed ready waiting for the end of the rest-time, when the first warm spring days shall open the tightly shut up bud-scales. In herbaceous plants which die down in winter and totally disappear, the winter buds are there too, in the tubers of orchids, in the bulbs of tulips, in the rhizome of the Solomon's Seal.
Perhaps the principal cause of the winter rest is the winter cold, the processes of plant life being only possible when the air and the earth are some degrees above the freezing point of water. But apart from winter's cold, a resting time seems a necessary condition of a plant's life. Under the most favourable conditions of warmth and sunshine, dormant periods occur; when everything seems to favour vital activity it nevertheless ceases--to be resumed months later at even a lower temperature. Many of our garden plants start into vigorous growth in spite of the winter's cold in February or March; they seem to have had their resting time and to be ready, under almost any conditions, to resume active life again. A potato tuber or an onion bulb will not put forth shoots in November, December, or January, even in moist, warm soil, but in February or March, in great cold or dryness, they cannot be prevented from doing so; and the winter buds of trees behave exactly as do these tubers and bulbs. As soon as the foliage and flowers are unfolded in the spring from the winter buds of the previous year, the winter buds of the next season are formed in embryo; they develop very slowly, and it is impossible by any known means to cause them to hasten on to leaf and flower without their resting time; yet in the earliest spring, branches of winter buds cut from the tree and place in water in a warm room, will there start hopefully into life though severed from their natural support. It seems likely that some internal change takes place in tubers, bulbs and buds, during the long pause; yet no striking chemical difference has been found in the composition of the potato tuber of spring from that of the autumn previous--on the contrary, the changes begin in the spring with the growth or germination. Reserve materials exist in two states; first, passive, inactive, dormant, whether solid or dissolved; second, dissolved, movable and active. In both animal and vegetable life peculiar organic compounds are found capable of converting the passive reserve materials into the active state; these are ferments. They arise from proteinaceous substances, but in such small amount that in some cases their existence is only inferred from their action; they seem to act as stimuli upon irritable organs; they are produced by the growing parts of seedlings or buds; they penetrate into the store of reserve materials and there dissolve and make them active. It is, therefore, now considered that the dormant period is used for the very slow production of ferments in the buds, and that it is only when they have been produced in sufficient quantity that the reserve materials can be put into the state of activity suitable for growth. The production of these ferments, too, may be directly promoted by the cold of winter. In the case of those tubers, buds, or seed which can grow immediately after production, it has been suggested that they may take up the necessary ferments from the mother plant.
I have been opening a lot of winter buds; their common characteristic seems to be a short, stout, succulent shoot, occupying about half of the bud, round which are packed tightly and closely the scales, while the tiny downy real leaves are on the upper part only. The oak buds contain three or four racemes of male flowers which I think are dead, as they are brown and withered looking; perhaps they have grown unduly owing to the heat of last summer or some other cause. The buds of the currant trees contain each a pair of leaves whose backs are decorated with glandular hairs, that glisten amber-coloured in the light, and in the centre is a bunch of tiny green flowers standing on the flat top of a short, stout shoot. The scales of the lime are fewer and much more succulent than those of the oak, while the enclosed leaves are scarcely to be recognized on account of their dense fur-like covering. The beech leaves are quite perfect in form, and they are green with a fringe and a thin covering only of long silky white hairs. The sycamore leaves like the beech are perfect in shape, quite green, but entirely hairless.
The flower buds of the laurel are very large, with many round buds in each one of them that are full of anthers. In the red-scaled terminal buds of the Scotch pine it is just the same, even the round pollen masses seem already distinguishable. On opening the currant buds the characteristic odour was very strongly perceptible, while from the laurel buds came a delicious scent of almonds.
Drawings give better than words some idea of the scaly armour that the trees put on, to protect from the frost and cold the centres of continuous life--the growing points. The oak and the Scotch pine have scales innumerable, the tulip-tree manages with but one or two, but they are very thick and tightly closed. That scales originate from leaf rudiments may be proved in several ways; on some trees one can find a series approaching gradually to leaf forms; scales have been caused to grow into leaves by depriving a plant early of its young leaves when the reserve materials forced into other channels build up other leaves from the scales. In the production of scales the part that might be the leaf blade never grows, though its existence may be demonstrated by the microscope, and the petiole alone develops abnormally. Cork is produced on the scales of some winter buds for their better protection, on those of the wych-elm, the hornbeam, the hazel and poplar.
One day in a time of hard frost, walking along a terrace road, with a ferny mossy wall on one side under tall straight Spruce firs that carpet the road red in winter with fallen needles, and a wide- reaching view on the other--where one looks from High Furness, which is Lancashire, across Westmorland lakes to Yorkshire moors and surmounting Ingleborough, a view that claims attention even in daily walks and militates greatly against a too thorough knowledge of the mosses and lichens of that ferny wall--I tried to notice how the different plants took the cold. The herbaceous flowering plants were certainly the most affected; there were numbers of well-grown young seedlings of the shining cranesbill, Geranium lucidum, with all their thickish red leaves hanging limp, the petioles fallen perfectly perpendicular; they looked like the wallflower leaves of the garden, lifeless past recovery, yet from past experience I knew that it is not so. The hardy polypody took the keen air much better and yet had got itself into very unusual position; all the green upper surface of the fronds were curled up and cuddled together, displaying only the paler backs studded with the golden spore spots that make such beautiful colour contrast. But the mosses were the best of all; the cold shriveled them not as did the heat of summer; and the grey cups and green flat surfaces of the lichens, too, seemed happy and indifferent.
The leaves of those trees and shrubs which remain all through the winter go through some state of internal change; an alteration takes place in the chlorophyll causing some change of colour; the leaves of yews, pines, juniper or box become discoloured, brownish or yellow or red brown, or even red on the upper side as in sedums, sempervivums and mahonia; the chlorophyll seems to retreat as far as possible from the surface or upper part of the palisade cells and its place is occupied by a substance in which tannin is found; or the chlorophyll quits the cell walls and masses itself together in the centre of each cell to take up its normal position again with the advent of spring.
II.--THE WINTER LIFE OF PLANTS
THE smaller forms of plant life, mosses and lichens, seem little affected by winter or summer; their living and growing time is when they revel in wetness, in dry seasons only they shrivel up and wait. In moist January days, moss life may be seen in every stage--the low walls that border the roads are long bright gardens which they have entire possession of, and which are at that time in perfection. Bryum argenteum bears thousands of crimson spore-capsules more profusely than the silvery foliage. Tortulas are sending up forests of pink and yellow spears that have not yet got as far as spore development in their summits. In rocky woods several species of hypnum are then fringed with double perisbomes.
On damp shady banks and walls the lichens are in good condition too, the large Peltigera canina has its dark green thallus folds with upstanding brown reproductive discs. Winter shows to us the evergreen life and marks how much there is; the golden-spotted polypody and the wallrue among ferns, the pine, yew, juniper among trees, and ivy with dense umbels of fruit of full size, but not yet turned black, each berry green with a cap of purple trimmed with calyx points and peaked with style. Gorse is profusely blooming, and there are other flowers the accidents of a mild winter. The crimson pistils of the hazel have been seen as early as the 8th of January; Saxifrage-tridactylites on a north wall have had one white flower in each dense rosette on the 20th; there are often some primroses in the woods; there is groundsel, there is chickweed; there is Poa annua; but these are only the ubiquitous accompaniments of a mild season, not true exponents of winter life. When a winter is coldest and the earth is bound by frost, and there is not one flower to be found, winter life still exists and there is something to be seen and noted. The majority of our flowering plants and ferns are more dependent upon heat than the lower forms--they cannot live and grow without it. They make preparations to protect themselves from the cold which otherwise would slay them, and in the winter time, the usual season of greater cold, their life--which is their protoplasm-- is buried, hidden, protected, covered up with many wrappings, kept tightly enclosed by many devices. All next summer's leaves and flowers are formed already and waiting somewhere; those of the herbaceous plants are only to be found by digging. I took up a decaying butterwort one autumn day, and found that the leaf bases enclosed a stout bud that lay an inch or more below the level of the ground; this large bud when opened displayed a miniature set of leaves and tiny flower groups, six perfect leaves and two flowers. It is only some few of the trees that display the flowers to the uninitiated eye, like the alder, the hazel and the birch, at this time of the year. These very evident catkins, formed in September before the fall of the leaf, grow apart, and the essential organs they bear are protected only by the firm and tightly-welded-together perianth scales. Other trees have the flowers wrapped up with the leaf-buds and enveloped in deciduous scales, which in the oak and beech are very numerous. Yet can the buds of these trees that contain flowers be told by their size in the winter preceding the flowering, and the forester knows thereby when to expect a crop of acorns or of beech most, since these trees bearing large fruits do not bear seed annually, but only at intervals varying from three to eight years. The woods of deciduous-leafed trees that have withdrawn their protoplasm from fragile leaves to firm stems and stout buds, are more varied in hue when bare in winter than when clothed with green in summer. Each species of tree has its own stem-form and colour, its own bud-form and colour, marking it off quite as closely as leaf-shape can do. Hence every tree is recognizable in its winter state. The pale-coloured twigs of the ash are accentuated by black velvet buds surmounting the pale scar of last year's leaf. The wych- elm buds are deeply red and there are two sorts of them, the leaf- buds that are pointed and at the ends of the branches, and the rounder flower buds below them. In any one of these branches the stem colour tells its history; the reddish ends of the twigs are last year's growth, the grey central stem below is older by one year.
The sycamore has green buds, a speciality of its own; its leaf scars are very clear. The buds of the horse-chestnut are very large and of rich sienna colour. All these buds show only their outer protective scales, which fall off when the leaves push through in spring; they vary in number greatly; willows have only one scale, limes two, alders three, and so on. When they are few they are tough and hard, when they are many they are thin and membranous. When the many scales of the beech fall in spring all the ground is coloured about the trees. The sycamore buds have seven pairs of thick solid scales enclosing the group of much smaller but already perfectly shaped foliage leaves in the centre. The foliage leaves and flowers within the horse-chestnut buds are thickly downy-like masses of cotton wool. The interior of a bud of an oak tree, seen in section, reveals there some six to eight leaves in the centre, three catkins of male flowers and innumerable scales, these, the enclosing organs, being greater in bulk than those enclosed. I wish to dwell upon the surface of plant life in the winter time and the beauty and variety of it. In a winter hedge-row with the sun shining on it, I often see lovely colour pictures; when ash, hazel, birdcherry(?), blackthorn or whitethorn are mingled with arching trailers of rose bearing hips, the wayside is prettier even than in leafy June. There is variety and differentiation in the trees themselves and their various parts. Take two branches from the hawthorn, one from the upper part, as high as can be reached, and another from the lowest part; they will be found very different; the thorny one is from the lower part, where protection is needed from grazing animals, and consequently strong sharp spines are produced with the short leaf branches well behind, and so defended by them; the thornless one is from the upper part, far out of reach from the ground, where thorns would be needless and so are not produced. In this tree the leaf stems are different from almost all others in that they are so short and without internodes, just a dense of mass of broken-off leaf traces, each year's leaves being produced in a rosette or whorl immediately above the last year's with no recognizable interval of space. There seems to be a reason for this, too, since the strong spines endure for years, the leaves must remain behind them to be defended by them.
There is another interesting point; the upper and lowers surfaces of twigs and buds are of a different colour. This is very marked in willow and hazel, the surface turned towards the sky is red, the other one is green. This must be in connection with cold and radiation, to which upper surfaces will be exposed more than under ones, and therefore they are strengthened against cold by red, brown or yellow colouring matter, as are many evergreen leaves in seasons of great cold, as are small unicellular plants, Protocoeus and other Algae, culminating in the real snow, Sphaerella nivalis, which has perhaps the coldest habitat of any known plant!
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