EVOLUTION OF VEGETAL LIFE.* In touching the question of development, even as it affects the most insignificant plant, we are feeling the pulse of the deepest mysteries: "To me the meanest flower that blows can give On the 26th of last July I was wandering around among the rocks where Cape Ann thrusts her granite arm out into the turbulent Atlantic, and bears from hour to hour through the ages the buffeting thunder-strokes of its mighty surf. The breeze was fresh; bright sunlight was reflected from the orange-gray rocks; and the air was full of the perfume of the bay-berry. But perhaps most lovely of all, where all was charming, was the myriad of wild roses which covered the bushes springing from the stony soil. We all know and love these delicate blossoms, which everywhere make our roadsides so attractive at midsummer. Professor Gray enumerates six species as growing in the Northern United States, and some varieties of these are to be found in almost every locality where there is a trace of wildness left. I have here roses from a bush of a different character, but we shall hardly say that they are less lovely. I want to ask you to follow me in an inquiry into the stages of the development of the bush from which they were taken; the different steps of growth which occurred before I could place before you these royal blossoms. In what shape did it first appear as a growing plant? Probably as a short cutting from a branch, bearing a few buds, and inserted for a part of its length in sandy loam: that is, it was simply a part of another bush. The bush from which it was taken doubtless originated in the same way, and so back for many generations, or quasi-generations, for, as a matter of fact, we have here no change by generation, but simply the prolongation of the life of a single * COPYRIGHT, 1889, by The New Ideal Publishing Co. plant, by cutting off the root, and bringing the branch into immediate contact with the soil and its contained fluids. By this means its life may be prolonged far beyond what is ordinarily its duration if left to grow from the original root, but not always, perhaps, beyond what is possible in such case of a rose-bush still living at Heldersheim, in Germany, it is said that, 800 years ago, Bishop Hepilo caused a trellis to be erected to support it. For the purpose of my illustration, I can most safely go far back of the plant which produced the roses before us, and perhaps may as well take one of those in the thorns of which I became entangled by the margin of the sea. Those of you who are familiar with botany will pardon the introduction of some rudimentary facts, which are essential to the systematic development of the idea which I am to present to you. We find, then, upon the summit of the flower stem, a little green urn or cup, dividing into five leafy points, and supporting upon its inner edge the five pink petals and a numerous colony of stamens crowned with yellow anthers; while within the cup are many tiny sacks, to each of which is attached a pistil having its summit slightly changed into what is called the stigma. When the flower is completely developed, we find that the anthers open and drop golden pollen-grains upon the stigmas below; and sufficient subsequent examination under a microscope shows us that from each live pollen-grain there grows a slender thread, which gradually penetrates to the little sack or ovule beneath. We next find formed, within the ovule, a minute cell: a membrane called cellulose, consisting chemically of carbon, oxygen and hydrogen, containing a semi-fluid drop of a substance called protoplasm, and consisting of the same elements, with the addition of nitrogen. I cannot tell you just how large this cell may be, but the ordinary diameter of cells in vegetable tissue varies between 1-240th and 1-1200th of an inch. If we take the largest of these, a cubic inch would contain about 14,000,000 of them. But whatever its size, this cell carries the promise and the potency of the plant which is to be. It is not the primary form of vitalized matter, for this matter exists as mere protoplasm alone, without a membrane. In its earliest condition we should be unable to tell whether this protoplasm is the initial step in the formation of a microscopic being not distinguishable either as plant or animal, or whether it is to be a rose, a violet, a palm or an oak,- a worm, a fish, a lion or a man. Its future is absolutely unpredictable, and yet upon it have been impressed or within it are contained the influences which determine which of these forms it shall take, in what way it shall resemble other beings, and in what way be distinguished from them: whether it shall live a stationary life, rooted to a rock or to the soil,-accepting the fate which the winds and the waters bring it,- or whether it shall have the power of flying to "fresh woods and pastures new"; whether it shall be a characterless automaton, or whether it shall speculate upon the origin of things, and upon life and death, the infinite and the absolute. If we follow the changes in this cell, we find it gradually becoming larger, and dividing by a partition into two, into four, and so on, until a tissue is formed; into a substance having perceptible length, breadth and thickness. At last we recognize it as a seed: two minute leaflets attached to the rudiment of a stem, all enclosed within a surface membrane. This is now distinctly the beginning of a plant, and with numerous others it is contained within the orangecolored "hip." In this state it is quiescent, but if after a time we place it in the earth, we shortly find it burst its sheath: the stem lengthens and pushes downward; the leaflets, reaching toward the surface, separate, and from between them there rises a sprout. How is this done? Simply by the increase in size, and the multiplication of the cells already formed, by absorption of the necessary chemical constituents found in the soil. But these cells now have a more definite arrangement. Some form a white root, and some a stem also white, until it thrusts into the air and light the point of a leaf, which immediately takes a tint of green. From this time on subsistence is not drawn from the soil alone, but from the air also. The leaf is not simply the right bower of the plant; it is its essential, I might say its only essential organ. There are, it is true, some plants which get along without leaves; such, for example, as the bright orange-colored dodder, common in our meadows and by the brooksides, trailing its long thread-like stems over shrubs and herbs, a golden network, with never a leaf, but with clusters of white blossoms. But these are lazy rogues, mere parasites, which do not even remain rooted in the ground, although they start there, but which attach themselves to other plants, and, too indolent to manufacture their own sap, plunder the vegetables, to which they have affixed themselves, of the material which they had provided for their own growth. There are numerous other plants not growing from the soil, such as the air-plants, with their gorgeous, or their fantastic insect or birdlike flowers; but these, to do them justice, are not so wholly idle and degraded: they are provided with leaves with which they earn their own living; they do not draw nourishment from the trees upon which they are found, but merely use them for support. As the cells become more numerous, they also become more and more diversified in structure. In different parts they are different in form, in size and in their nature; some are very beautiful; most are small, but others take the form of tubes, and are enormous, having a length in some instances as great as one-sixth of an inch! But this is an extreme case. The crude ingredients for the sustenance of the plant are absorbed by the root, and transferred from one closed cell to another, through many millions it may be, until they reach the leaves, where they are mixed with the constituents of the atmosphere, and elaborated into the protoplasm from which the plant is built up. The rapidity with which this transference may take place you have yourselves noticed, when you have taken a drooping flower and placed it in a vessel of water. How soon the stem, leaves and blossom regained their firmness, their rigidity, their elasticity, their "life"! The plant now sends up a stem upon which appear buds; these unfold into leaves; branches grow from the axils of the leaves, and leaves appear upon these in turn, and thorns form, by which the plant is defended. A flower is no necessary part of a plant; it is but one means of providing for a continuance of the series. The flower itself is but a series of modifications of a cluster of leaves, some of which have become sepals, some petals, some stamens, and some pistils. At a recent meeting of the Royal Horticultural Society in London, an Alpine strawberry was shown in which all parts of the flower were more or less represented by leaves. The strawberry is a near relative, a sort of cousin-german as it were, of the rose. We have now completed the cycle. Starting from the flower, we have followed the life-steps until we have reached it again. Another course which we might have adopted, the one ordinarily chosen by fruit-growers, is that of budding or grafting. We should then have simply taken a single bud in the one case, a small twig in the other, from the variety which we desired to propagate, and inserted it into a sturdy stock of a nearly related kind, in which we had made an incision, bringing the inner bark into close contact, and excluding the air from the joint. What is the result of this process? Excepting in a few special cases, which I cannot stop to describe, the line of union between the two growths becomes indeed a line of union, but remains a line of separation. It is like the door of the underworld of which Dante speaks, though perhaps the prospect is not so hopeless. Your quince or crab stock is firmly rooted in the ground; it draws thence its juices and transfers them from cell to cell, to those of the new bud; but here they "suffer a sea change into something rich and strange." Your bud multiplies its cells,- becomes a twig,—a branch; it buds, it blossoms, and instead of the woody but fragrant quince, the rosy but diminutive crab-apple, you gather the pearmain, the wine-sap, or the seek-no-further, as you may have elected. But stop. Do you always gather a fruit exactly like that with which you were familiar? Do you invariably obtain from the seed or cutting of your rose a flower of the same identical tint of the same form, of the same fragrance? Not so: you find slight differences, for the better or for the worse; scarcely any two are precisely alike; you choose those that you prefer and propagate them; you neglect the others. We have seen that Gray enumerates six species of wild roses in the Northern United States. There are also a number of wild species in the Eastern Hemisphere-how many I cannot tell you. But their cultivation began at an early date, and they have been developed and crossed inextricably. In 1793 some wild Scotch roses were transplanted into a garden. One bore flowers slightly tinged with red; from this, double roses were developed, blush, crimson, purple, red, marbled, two colored, white and yellow, and differing as much in size and shape. In 1841 the number of varieties in the nursery-gardens near Glasgow was estimated |