whole subject of variation in species, the existence of varieties, and also of those partial sports, which may perhaps be considered as still more temporary variations from the originals, than those which come through the seeds, is one of deep interest, well worthy of our study, but concerning which we must confess ourselves as yet quite ignorant, and our best botanists do not agree even as to the specific distinctions that have been set up as characters of some of our familiar plants, for the most eminent differ with regard to the species of some of our common trees and plants.
RUNNING OUT OF VARIETIES
It has been a very generally received opinion among intelligent fruit-growers, that any given variety of fruit can have but a limited period of existence, be that longer or shorter. Reasoning from the analogies of animal life this would appear very probable, for it is well known that individuals of different species all have a definite period of life, some quite brief, others quite extended, beyond which they do not survive. But with our modern views of vegetation, though we know that all perennial plants do eventually die and molder away to the dust from whence they were created, and that many trees of our own planting come to an untimely end, while we yet survive to observe their decay, still, we can see no reason why a tree or parts of a tree taken from it, and placed under circumstances favorable to its growth from time to time, may not be sempiternal. Harvey has placed this matter in a correct light, by showing that the true life and history of a tree is in the buds, which are annual, while the tree itself is the connecting link between them and the ground. Any portion of such a compound existence, grafted upon another stock, or planted immediately in the ground itself and established upon its own roots, will produce a new tree like the first, being furnished with supplies of nourishment it may grow indefinitely while retaining all the qualities of the parent stock—if that be healthy and vigorous so will this—indeed new life and vigor often seem to be imparted by a congenial thrifty stock, and a fertile soil, so that there does not appear to be any reason why the variety should ever run out and disappear.
The distinguished Thomas Andrew Knight, President of the London Horticultural Society, was one of the leading advocates of the theory that varieties would necessarily run out and disappear as it were by exhaustion.
In his Pomona Herefordiensis, he tells us that "those apples, which have been long in cultivation, are on the decay. The Redstreak and Golden Pippin can no longer be propagated with advantage. The fruit, like the parent tree, is affected by the debilitated old age of the variety." And in his treatise on the culture of the apple and pear, he says: "The Moil and its successful rival, the Redstreak, with the Must and Golden Pippin, are in the last stage of decay, and the Stire and Foxwhelp are hastening rapidly after them." In noticing the decay of apple trees, Pliny probably refers to particular trees, rather than the whole of any variety, when he says that "apples become old sooner than any other tree, and the fruit becomes smaller and is subject to be cankered and worm-eaten, even while on the trees."—Lib. XVI, Chap. 27.
Speechly combated the views of Mr. Knight, and says: "It is much to be regretted that this apparently visionary notion of the extinction of certain kinds of apples should have been promulgated by authors of respectability, since the mistake will, for a time at least, be productive of several ill consequences."
Some of the old English varieties that were supposed to be worn out or exhausted, appear to have taken a new lease of life in this country, but we have not yet had a long enough experience to decide this question. Many of the earlier native favorites of the orchard have, for some reason, disappeared from cultivation—whether they have run out, were originally deficient in vigor, or have merely been superseded by more acceptable varieties, does not appear.
Mr. Phillips, in his Companion, states "that in 1819, he observed a great quantity of the Golden Pippin in Covent Garden Market, which were in perfect condition, and was induced to make inquiries respecting the health of the variety, which resulted in satisfactory replies from all quarters, that the trees were recovering from disease, which he thought had been induced by a succession of unpropitious seasons. He cites Mr. Ronald's opinion, that there was then no fear of losing this variety; and Mr. Lee, who thought that the apparent decay of some trees was owing to unfavorable seasons. Mr. Harrison informed him that this variety was very successfully grown on the mountains of the island of Madeira, at an elevation of 3000 feet, and produced abundantly. Also that the variety was quite satisfactory in many parts of England, and concludes that the Golden Pippin only requires the most genial situation, to render it as prolific is formerly."
It is quite probable, as Phillips suggests, that Mr. Knight had watched the trees during unfavorable seasons which prevailed at that period, and as he found the disease increase, he referred it to the old age of the variety, and based his theory to that effect upon partial data.
Mr. Knight's views, though they have taken a strong hold upon the popular mind, have not been confirmed by physiologists. For though the seed would appear to be the proper source whence to derive our new plants, and certainly our new varieties of fruits, many plants have, for an indefinite period, been propagated by layers, shoots or scions, buds, tubers, etc., and that the variety has thus been extended much beyond the period of the life of the parent or original seedling. Strawberries are propagated and multiplied by the runners, potatoes by tubers, the Tiger Lily by bulblets, some onions by proliferous bulbs, sugarcane by planting pieces of the stalk, many grapes by horizontal stems, and many plants by cuttings, for a very great length of time. The grape vine has been continued in this way from the days of the Romans. A slip taken from a willow in Mr. Knight's garden pronounced by him to be dying from old age, was planted in the Edinburgh Botanic Garden many years ago, and is now a vigorous tree, though the original stock has long since gone to decay.11
CHAPTER III
PROPAGATION.—SECTION I
ALL GROWTH IS DEPENDANT UPON THE DEVELOPMENT OF CELLS—THE SEED AND THE BUD; THEIR RESEMBLANCE—THE INDIVIDUALITY OF BUDS—THE BASIS OF ALL PROPAGATION—BUDS ARE DEVELOPED INTO TWIGS; HAVE POWER OF EMITTING ROOTS—IMPORTANCE OF THE STUDY OF CELL-GROWTH—BY CUTTINGS: PREPARATION AND SELECTION—HEEL-CUTTINGS—SOFT WOOD—HARD WOOD—SEASONS FOR EACH—FALL PLANTING—THE CALLUS, OR DEVELOPMENT OF CELL-GROWTH—BOTTOM HEAT; WHY BENEFICIAL—WHY SPRING CUTTINGS FAIL—STIMULUS OF LIGHT UPON THE BUDS, CAUSES THEM TO EXPAND, AND THE LEAVES EVAPORATE TOO FREELY—ROOT CUTTINGS; DIFFERENT FRUITS THUS PROPAGATED—BY SUCKERS: OBJECTIONS TO ANSWERED—SUCKER ORCHARDS; BEAR EARLY—SUCKER TREES APT TO SUCKER AGAIN—BY LAYERS: A NATURAL METHOD—HOW PERFORMED—THE RASPBERRY AND THE GRAPE—ILLUSTRATIONS OF NATURAL AND ARTIFICIAL METHODS—QUINCE STOCKS—ADJUVANTS TO LAYERING, NOTCHING, ETC—BY SEEDS: HOW IT DIFFERS FROM THE OTHERS—APPLE SEEDLINGS—THEIR TREATMENT, SEPARATING, AND PREPARING THE SEED—APPARATUS—SPROUTING—SOWING—CULTIVATION—SEEDLINGS—TREATMENT—SORTING—PACKING.
All propagation of plants must depend upon the development of seeds or of buds, and all will arise from the growth and extension of cells. The seed and the bud are much more nearly related than a casual observer would at first sight suppose. The early phylologists thought they discovered that in the seed was enwrapped the image of the future tree—a dissection of the seed would appear to demonstrate this. It is composed of separate parts which are capable of being developed into the root, stem, and appendages, but they have yet to be so developed; the several parts that we find in the seed are merely the representative parts. But the seed has the future of the tree within itself, it has certain qualities of the future tree impressed upon it in its primary organization, within the capsule of the fruit of the parent plant, so that in a higher sense the image of the future tree does exist within the seed. Within the bud, still more plainly and more distinctly visible, is the future tree manifest, and we may produce a tree from a bud as certainly as we do from a seed. Subjected to circumstances favorable for growth, the bud, as well as the seed, will emit roots, will form its stem, branches and appendages, and will become a tree; differing from the product of the seed only in this, that in the latter
Balfour's Manual, p. 284.
