Under drought conditions the temperatures of the air and of surfaces exposed to the sun are often very high, and this sometimes results in sun-scald or burning of the hulls or shucks. In severe cases the injury extends through the hull or shuck to the shell and kernels. The pellicle, or skin of the kernel, turns brown or amber color, as does the portion of the kernel that has developed at the time of injury. Further development of the affected portion of the kernel is arrested; and on drying it becomes shriveled because of lack of filling. The greatest amount of damage from sunburn occurs on the south and southwest sides of the trees. Little can be done to prevent this type of injury other than to grow good, strong, vigorous trees that bear a heavy dense foliage that shades the nuts. +Heterosis or hybrid vigor:+ The pistillate flowers of certain nut species, such as the almond, chestnuts, and filberts, must be cross-pollinated with pollen from another variety if satisfactorily crops of well filled nuts are to be produced. These species are self-sterile or self-unfruitful. On the other hand all walnut, pecan, and hickory species are self-fertile and cross-fertile, but may be self-unfruitful because of dichogamy, because they may shed their pollen either before or after the stigmas of the pistillate flowers are receptive to it. In all nut species cross-pollination is generally recommended so as to assure a set of nuts. With cross-pollination a better set of nuts is to be expected than with self-pollination, as well as better filling of the kernels. It has recently been found that when the pistillate flowers of a certain variety are cross-pollinated with a pollen from another definite variety the embryo or nut kernel is larger and better filled. This is a manifestation of hybrid vigor, or heterosis. Heterosis has been found in the chestnut and in the pecan. It likely will be found in other nut species. Some day the principles of selected and controlled parentage underlying hybrid vigor may be utilized in producing superior nuts, as these principals are now so widely used in producing hybrid seed corn. * * * * * President Davidson: That paper was so extremely important that I hesitated very much to stop it, but we are already at the point where we should have adjourned. Now, unfortunately, we have some very important things, I think, yet before us, but if the speakers can give their talks from now on in the form of, shall we say, syntheses of the whole thing and give us the conclusions rather than the details, it will be appreciated by us all. Mr. Wilkinson is going to give us a very important talk on what he has done with the propagation of the Lamb curly walnut. Mr. Wilkinson. The Grafted Curly Walnut as a Timber Tree J. FORD WILKINSON, Rockport, Indiana