Mr. Wilcox: It was a cross between Juglans Californica and the live oak.
The Chairman: Both the foliage and the nuts were very remarkable and pertained to characters of these two trees. Such a cross to my mind would be wholly unexplainable excepting on the ground recently brought out by Loeb and his followers in crossing the lower forms of animal life and finding that the cell membrane of the egg, if destroyed, will allow of very wide fertilization subsequently with other species. It occurs to me now--I had no explanation last year, but it occurs to me now, knowing of Loeb's experiments--that it is possible that one of the parents, the parent California oak tree carrying the female flowers, might have had its sex cells subjected to some peculiar influence like acid, sulphurous acid, for instance, from some nearby chimney. Sulphurous acid perhaps from someone merely lighting a match to light a cigar under the tree; he might have so sensitized a few female flowers, may have so injured the cell membrane of a few female germ cells that cross pollinization then took place from a walnut tree. It is only on some such ground as the findings of Loeb that we can explain such a very unusual hybridization as that, which appeared to me a valid one, of a cross between an oak and a walnut.
(Secretary Deming then called attention to hybrids in the various exhibits.)
Professor Smith: I should like to ask why, if this free hybridization takes place in nature among the hickories, you do not have a perfect complex of trees showing all possible variations in the forest.
The Chairman: In answer to Professor Smith's question I will start from his premises and remark that we do have such complexities. The hickories are so crossed at the present time, like our apples, that even crossing the pollen of various hickory trees of any one species does not promise interesting results unless we cross an enormous number. They are already so widely crossed that it is very difficult sometimes to determine if a certain tree is shagbark or pignut or shellbark or mockernut. For the most part the various species and varieties of hickories retain their identity because their own pollen is handiest, and different species do not all flower at the same time. Their own pollen from the male flowers is apt to fall at the time when their own female flowers are ripe and under these circumstances the chances are very much in favor of the tree pollinizing its female flowers with its own pollen. On the other hand, there is hardly one chance in many hundred thousand for any crossed nut to grow, for the reason that most nuts are destroyed by mice, squirrels, rats and boys. If you have a hickory nut tree growing in a lot, and which has produced a bushel of hickory nuts year after year, do you know of one single nut from that tree which has grown? In this plan of Nature, this plan of enormous waste of Nature in order to get one seed to grow, the chance for a hybridized hickory nut to grow under normal conditions, is so small that we should have relatively few crossed trees growing wild in Nature, though we do find quite a good many of them.