April 2, 1890.] 



Garden and Forest. 



163 



valuable to all of us, but in a particular degree to those who 

 practice the cultural arts. And so it happens — or, at least, we 

 will hope so — that although the causes which have been as- 

 signed for these changes are various, some, perhaps, utterly 

 wrong, others partially so, and all more or less inadequate to 

 explain the whole of the phenomena, yet some advantage may 

 accrue from the discussion. An indirect benefit is better than 

 none at all, and anything which enforces us to take some 

 measure of the extent of our own ignorance is likely to be 

 beneficial. We should never be a bit the better if we simply 

 acknowledged our ignorance, as, indeed, we needs must do in 

 any case, but directly we attempt to find out in what particulars 

 and in what degree weare ignorant, then there is some hope that 

 some portion of our "nescience " may bedispelled. Under this 

 impression we may allude to one or two of the assigned causes 

 of sporting. External causes are those which the gardener 

 most generally invokes. For him a sport is usually the con- 

 sequence of some alteration in the nutrition of the plant. It 

 gets too much or too little food, or the food is not of a suit- 

 able character — containing too much of one thing, too little of 

 another, or the climate is charged with the results observed. 

 It is very convenient to have the weather to blame ; it may be 

 too hot or too cold, too moist or too dry, too brilliant or too 

 obscure ; or the soil may be at fault, the drainage may be de- 

 fective, the earth not sufficiently aerated, its temperature too 

 high or too low. Combined action of some of these condi- 

 tions is, of course, possible, intermittent action equally so, 

 whilst we, in this country, are abundantly familiar, first, with 

 one thing in the way of the weather, and immediately after- 

 ward with another. It is, therefore, not surprising if some 

 gardeners, without troubling themselves much to see how the 

 explanation fits the facts, do attribute " sports " to such causes 

 as we have mentioned. To our thinking the objections to this 

 kind of explanation are fatal. External circumstances are, no 

 doubt, potent enough to effect very great changes indeed. We 

 are daily witnesses of them; but they do not produce the kind 

 of change which we know as "sports." On the contrary, 

 sports occur sometimes when no alteration of external condi- 

 tions is perceptible, and they do not occur when such altera- 

 tions are very apparent. Or, again, they appear in one place 

 under one set of circumstances, and at another place, simul- 

 taneously, under a different state of affairs ; and although all 

 the plants growing together have been exposed to the changed 

 conditions of life, the sporting tendency shows itself in one par- 

 ticular plant only, and in one particular part of that plant, gen- 

 erally only in one bud. With all respect, then, for those who hold 

 these views — and one at least of our most experienced and 

 eminent plant-growers has lately publicly advocated them — 

 we venture to think external causes, however adequate they 

 may be in some cases, are inoperative in such cases as we 

 are considering. 



A better explanation is that offered by Darwin, by Naudin 

 and others, according to which sports are due to a dissocia- 

 tion of mixed elements, a reversion to the character pos- 

 sessed by one or other of the ancestors of the plant, perhaps 

 one or two, perhaps an indefinite number of generations ago. 

 Let us recall for a moment what a very composite thing a 

 plant is, even such a one as we call a simple plant. At first 

 it is neutral and homogeneous, a mass of protoplasm — con- 

 taining cells — at least so it was once said, but the homogeneity 

 of protoplasm is a thing of the past. We don't believe in it 

 now. On the contrary, we believe in frameworks and inter- 

 stitial fluid, in granules and fibres, in some parts that are 

 alive, others that are dead ; some that are stable and immu- 

 table, others that are mobile and changeable ; in short, we 

 have come to the conclusion that, physically and mechan- 

 ically, as it was previously known to be chemically, proto- 

 plasm is very much " mixed." 



Again, another of our old beliefs has been dissipated. Once 

 we were taught that the cells of plants were closed bags with- 

 out apertures, and that, while the fluid passed from cell to cell 

 by osmosis, there were no visible pores, and no means of 

 transmitting anything more solid than cell-sap. The passage 

 of protoplasm from cell to cell was not then thought of as 

 possible. But Mr. Walter Gardiner has changed all that. He, 

 and others who have followed in his steps, have taught us 

 how to see the pores in the cell-walls, how to see the pas- 

 sage of protoplasm through those pores from cell to cell, 

 and how complacently to employ the phrase "continuity of 

 protoplasm " in a manner that gives us, at present at least, 

 great satisfaction. These modern discoveries of the com- 

 posite nature of protoplasm, and of its passage, at certain 

 times and under certain conditions, from cell to cell, seem to 

 us to furnish a clue to the explanation of some of these cases 

 of sporting as they do also in the case of some of those 



curious cases in which the stock seems to influence the scion, 

 or the scion the stock, in cases of grafting. 



Again, in the life history of a plant there are several stages. 

 There is the neutral stage, when it is, at any rate, so far as sex 

 is concerned, an epicene. Then there is the sperm stage, 

 when our plant consists of a mass of neutral matter, a par- 

 ticular portion of which is developed into sperm-cells, or into 

 what will ultimately produce them. At another time the 

 neutral cells of one portion of the general plant-mass develop 

 into germ or female cells, or it may happen that both sperm 

 and germ-cells may be developed at one and the same time, 

 when the plant has, of course, a three-fold constitution. 



All these modifications occur in the course of the life of 

 each individual plant. But each individual plant is, neces- 

 sarily, compounded of elements derived from its two parents, 

 so that, for illustration sake, if we may consider the original 

 stock to consist of three portions — neutral, male and female, 

 respectively — it is obvious that in the first generation there 

 would be six component elements ; in the second, twelve ; in 

 the third, twenty-four, and so on. Who can count the gen- 

 erations of plants ? It is enough for our purpose if we suc- 

 ceed in showing clearly the composite nature of plants. 



This being granted, it will not seem remarkable that occa- 

 sionally a partial separation takes place, just as a scum may 

 rise to the surface of some mixed fluid, or a sediment fall to 

 the bottom of another. This illustration may, perhaps, serve 

 to suggest the reason for the separation of mixed elements in 

 plants ; but that is too speculative a matter for us to enter 

 upon here. It will be better for our present purpose to note 

 one or two examples of dissociation of mixed characters 

 wherein both the fact and its explanation are clear. One 

 of the most interesting is that narrated by Mr. Noble, the 

 originator of the white form of Jackman's Clematis. Noble's 

 Clematis, as we may here shortly call it, is the result of a 

 cross between Jackman's Clematis and C. patens. Soon after 

 this Clematis was sent out, some dissatisfaction arose because 

 instead of producing flowers of good form and purity of 

 coloring, more or less misshapen blooms of an unattractive 

 appearance were formed. The matter was mysterious. The 

 raiser was blamed by those who did not know that he is a 

 highly competent man in his business, and one whose in- 

 tegrity is beyond question. 



The plant was condemned. Fortunately, however, the 

 edict was not carried out in its entirety — some specimens were 

 left. These were watched, and in due time afforded the explana- 

 tion of the mystery. Jackman's Clematis flowers in the 

 autumn on shoots formed during the spring and summer — on 

 the new wood, as gardeners say, just as happens with a Rose. 

 Clematis patens flowers in spring on shoots that were formed 

 during the previous summer, on the old wood, in gardening 

 phrase. Now, when Noble's Clematis came to be scrutinized, 

 it was found that it produced two kinds of flowers — those 

 which expand in spring are solitary, semi-double, never white, 

 but bluish gray, like those of C. patens. Those which unfold 

 in autumn are produced in pairs and are single, like those of 

 C. Jackmanni, but white. In the spring no flowers of the 

 Jackmanni type are ever seen, and when the old wood is cut 

 away, and only new wood thus suffered to produce flowers, 

 no blooms of the Patens character are seen, but only those of 

 the Jackman type. 



Another very interesting case of unmixing, or, if it be pre- 

 ferred, of partial mixture, is afforded by Neubert's Berberis. 

 This is a hybrid between the evergreen pinnate-leaved Ma- 

 honia and the deciduous, simple-leaved Berberis vulgaris, and 

 it bears leaves some of which are intermediate in appearance, 

 while others are like those of one or of the other of its parents. 



The two illustrations above given are instances of the 

 results of cross-fertilization, in which the whole process has, 

 so to speak, taken place under our own eyes. But for how many 

 centuries has the Chrysanthemum, we will say, been crossed and 

 recrossed and crossed again ? This process of crossing 

 seems destined to come to an end because the flowers, after 

 a time, become sterile, owing to the fact that the stamens and 

 pistils, one or both, are imperfectly or not at all developed. 

 Seedling variations in such cases must become more and 

 more rare as the process of sterilization becomes more and 

 more marked. If new seedlings are desired, raisers will have 

 to go back to less highly modified flowers, to flowers, that is, 

 which are more nearly in their original condition. But 

 although the production of varieties in the Chrysanthemum 

 by fertilization is thus limited, the development of sports bv 

 bud-variation may, and probably will, still go on, to the delight 

 of the grower and the interest of the student. It must, how- 

 ever, be said that atleast in the case of the Chrysanthemum the 

 change is sometimes very slight, depending solely on the 



