plants during the first and third seasons. It is of further interest to note that two of the plants, No. 5 and No. 13, which exceeded plant No. 8 in total yield the third season, also exceeded it in yield the first season, but that they fell below it in rank the second season. A similar result occurs upon the basis of the total number of flowers of the special and fancy grades with the same plants.

It may be inferred then that plants which produce especially high yields at times and fluctuate by crops also fluctuate by seasons or years.

IMPROVEMENT OF ROSE PLANTS BY SELECTION.

The question may properly be raised, at this point, is it not possible for the florist and the nurseryinan to greatly improve rose plants by propagating from individuals which show a marked advantage over others in total production of flowers or in the production of especially fine flowers.

There are several factors which make it necessary to look at the question from several view points. From the standpoint of the rose grower, vigor is the most important character to be recognized in a rose plant for this largely determines the total production and the quality of the crop, and thus the profits to be secured.

Successful rose growers recognize the importance of strong, vigorous cuttings, and the necessity of a continued vigorous growth after they have been rooted, and even after they have been benched; in fact this is a well known principle in rose culture. Cuttings from vigorous, healthy plants can be expected to produce strong plants if properly handled, as a vigorous cutting is almost certain to contain more potential plant food than a weak cutting.

SELECTED STRAINS OF ROSE PLANTS.

Is it possible for the rose growers to go even further than in the usual method of propagation, and by selecting cuttings from special plants to secure a selected strain of any variety which will be superior to the old strain in average production? From the results secured in these studies with My Maryland roses it would appear that there is some promise of success, but it would require time and much care in selection. It is evident that one plant might appear more vigorous than another, due to a more favorable location in the greenhouse bench. On the other hand a naturally vigorous plant might easily become weaker than another due to less favorable handling previous to benching, also to lack of proper care in the benching process and to numerous other factors. The results previously discussed in this paper also point out the fact that naturally strong and very vigorous plants may appear deficient in vigor and produce a light yield during certain periods lasting a number of months and covering several crops. It is not easy, therefore, to determine the best plants from which to begin the selection, which will result in a strain that will really be an improvement upon the original one.

The average florist cannot spare the time to undertake such a selection and will continue to propagate from ordinary strong and vigorous plants. The recording of yields of a large number of individual plants for a considerable period as in the studies at the New Jersey Station would require much time and expense. Florists might attempt the improvement of any particular lot of roses by noting the relative vigor of the plants just previous to any crop, and then to tag or mark any plants wn ch appeared especially vigorous, and which carried a large number of buds or flowers of good quality. Plants that are not favored by any factor of environment, should be selected and the observation of the behavior of the plants must be continued for several crops and for more than one season for best results.

When cuttings are taken from such selected plants, only strong and vigorous stems should be selected, as weak cuttings from naturally vigorous plants are not likely to succeed any better or even as well as vigorous cuttings from comparatively weak plants. Further selection work with the plants under observation in these experiments is being planned at the New Jersey station.

SELECTION WITH REFERENCE TO COLOR OF FLOWERS.

One frequently observes several shades of color among roses of the same variety in the florist's window. Dark pink specimens may appear with light pink, faded ou: appearing specimens. Nothing has been stated thus far as to selection upon the basis of improved color in the lowers. This involves a discussion of the factors which determine color in the forcing of roses. The numerous types of Killarney demonstrate that the rose not infrequently sports. These "sports" are sudden and distinct variations or mutations which can be perpetuated by propagation, but do not concern the matter of general variation in color of the great bulk of roses. It is not infrequently supposed that plant foods are the determining factors in the color of flowers, but it is very doubtful if such is the case except in an indirect way. It was observed early in the experiments with My Maryland toses at this station that light was the most important factor in the color of the flowers, and was reported by the writer at the seventh annual meeting of this society.

The petals of the My Maryland rose are devoid of pink color until exposed to the light by the opening of the bud, and gradually become deeper in color until they expand. Three days of dull weather at the New Jersey station in January occurring during the cutting of a crop of My Maryland roses, caused a change in the color of the crop cut from a dark pink to a light pink. Following a day of bright weather the opening uncut buds became a deep pink color. This behavior has been repeated frequently during the last four years, and by other varieties such as Killarney and Sunburst. Buds covered with black paper just before the petals showed remained much lighter in color than buds exposed to the light.

Rate of growth is also a factor in Jetermining color. Weak suc culent growth often means poor color of the flowers. This is correlated with the effect of light to a considerable extent, however, as a bud which matures very rapidly is exposed to the light for a shorter length of time than a bud which matures more slowly. Plants that are actually injured in growth by some factor such as soil acidity or excessive fertilization Lecome exceptions to the rules of behavior of normal plants.

The effect of light upon the color of the flowers is not confined even to the indoor forcing varieties of roses. Observations of the Dorothy Perkins show that the petals are practically white before they are exposed to the light and gradually assume the pink color when exposed. With the exception of true sports it is not believed that selection of rose plants for gradual improvement in the color of the flowers is possible. Florists should be encouraged to select their cuttings for prepagation from the strongest and most vigorous plants as many are doing today, but the securing of special and productive strains, aside from sports, by careful records of individual yields is sure to prove a long process.

SOME INVESTIGATIONS IN GRAFTING.

BY N. O. BOOTH, Experiment Station, Stillwater, Oklahoma.

For some years the writer has been interested in the general subject of grafting, and particularly that phase of the subject which concerns its advantages and disadvantages as a horticultural practice.

It has been frequently stated, but probably without much evidence to support the statements, that a graft in a plant is a weakness in the plant, and that the ungrafted plant is stronger than the grafted one. Some years ago the English author, Burbridge, took the somewhat radical stand that grafting and budding plants is a laborious and faulty method of propagation, and that it is really up to the nurserymen of the world to find some easier method that would produce stronger plants. He further states that in his estimation the nurserymen would have done so before this if the plant buying public had only insisted that they do so. Up to within a recent period, however, these discussions have been seldom or never scientific. A mass of unrelated evidence is ordinarily brought to support one or another view. Quite recently Daniels. the French investigator, has conducted some very brilliant investigations along this line, and in particular has thoroughly gone over the literature of this subject, back to the earliest times, showing exactly how much we know about grafting.

It may be wise to briefly outline the fundamentals of grafting. Budding and grafting are two essentially similar operations fre quently included under the general name of "graftage." In both budding and grafting a portion of the top of one plant is spliced onto the root, or the root and a portion of the top, of another plant,

in such a manner that the two grow together and produce a new plant with the top of the one and the root of the other. It is generally supposed that in such cases the root retains the characters of the plant from which it came, and the top characters of the plant from which it came. There are some, however, who question this. Looking at the subject from the standpoint of plant anatomy and physiology, there are several ways in which the graft may be a weakness. First, there may be a physical weakness at the point of union. Second, the leaves of the scion plant may find difficulty in elaborating the sap taken up by the roots of the stock plant. Third, the root of the stock plant may find difficulty in assimilating the plant food manufactured in the leaves of the scion plant. Fourth, there may be an interruption to the upward flow of sap, due to faulty connection of the xylem vessels at the point of union. Fifth, there may be an interruption to the downward flow of sap owing to a faulty union of the phloem. Sixth, the quantity of sap taken up by the root may be either too great or too little for the proper supplying of the scion plant above. Seventh, the amount of elaborated sap furnished by the scion plant may be either excessive or deficient in amount for the proper nourishment of the stock portion of the plant.

The first point to be considered, that of physical weakness, is a very difficult one to settle conclusively owing to the variation which may be found in different trees and with different combinations of scion and stock. Something over a year ago a test of this matter was started at this station. A comparatively few trees have been tested, as yet. Material was secured from a ten year old orchard growing on the college campus. It is a mixed orchard of peaches, apricots, and plums. With the plums and apricots it was quite easy to secure material showing very plainly the point of union. In the case of the peach, however, with trees which were known to be budded, the points of union were not nearly so evident. To test the breaking strength of plum and apricot wood at different points, longitudinal sections about two inches square and twelve inches long were made through the union. The plum section gave the following results:

To eliminate the possible discrepancy due to the breaking point. of the union being closer to the ground, and hence possibly in softer wood, the next block, being particularly long, was broken both above and below the union, as well as at the union.

*This work was done through the kindness of the Engineering Department of this Institution, with their machine and by one of their workers.

Strip No. 1 broke at point of union with 1330 pounds pull. Same strip above point of union broke with 1550 pounds pull. Strip No. 2 broke slightly below union with 2870 pounds pull. It broke slightly above union with 1770 pounds pull but would not break at union.

All of the above tests were made with quite green wood within three weeks after the trees were taken out. This was done purposely as the green wood seemed to represent more nearly the condition in the growing tree than the seasoned timber would. In the next test, however, the wood tested had been seasoning nearly four months, and was quite thoroughly dried out.

TEST OF TRANSVERSE BREAKING STRENGTH.

Apricot No. 2, 1st. block..

At point of
union.
1,930 pounds

Above point of

union. 4.355 pounds

This phase of the subject is still under test with more blocks of different kinds of wood which will be broken. The results. however, are very positive, and it does not seem at all likely that further tests will invalidate the statement; that for many trees the point of union is a real and evident physical weakness. It is true. however, that all three trees tested were apparently strong, had made a vigorous growth, and had never been broken in any way. They were about eight inches thick, and about ten years old. For orchard purposes this weakness does not appear to be of importance. There is also no question but that the thickening of the trunk which usually shows at the point of union, may lessen materially the weakness of the trunk at this point.

The next phase of the subject is that as to whether the leaves of the scion plant have difficulty in elaborating the sap furnished by the roots of the stock plant. This is really a question in general plant physiology on which considerable light may be thrown by the answer to the question as to whether any roots have the power to discriminate in taking up soil mo'sture. If the roots of higher plants generally have such power, then it is quite likely that the sap taken up by one plant would not suit the leaves of another and quite different plant. There appears to be some difference of opinion among plant physiologists on this point, but it is generally agreed that such power of discrimination, if it exists, is slight, and and is controlled largely if not wholly by the ultilizing of