On December 14, 1943 I received a second, and final report from Dr. McKay from which I quote, as follows: 

     “Dear Mr. Weschcke: 

The enclosed pencil sketches will give you an idea of the results obtained from sectioning four lots of material from the two samples of catkins that you sent, two lots from each sample.  Since the sample collected May 25 at the time of catkin fall was old enough to contain mature pollen and showed only anthers of the two types described herewith I think we may safely conclude that the tree is male sterile because of the failure of the mother cells to function.  It is odd that in some anthers the pollen-mother-cells develop (type 2) while in others they do not (type 1).  For this we have no explanation; nor can we explain why the tree is male sterile.  I am afraid these phenomena will remain a matter of conjecture for some time to come.  Since sterilities of this and other sorts in most other plants are largely genetic, that is, controlled by one or more genes that are inherited in Mendelian fashion, it is likely that such is the case here.  You and I will not live long enough, however, to grow the necessary number of generations of trees to clear up these matters.

“In the course of routine preparation of other material I plan to run up other lots from your samples, and I will let you know if anything different turns up.  I believe we may safely conclude, however, that the results reported herewith are representative.”

In further explanation, Dr. McKay submitted the drawings shown on page 57, and says: 

“Four lots of material were sectioned, two from the collection of May 6 and two from that of May 25.  Of these, two gave anthers of type one, and two of type two.  More material will have to be sectioned before we know which type is predominant.

     “The anthers of type one are greatly shriveled, and a band of
     deeply-staining collapsed cells apparently represents the remains
     of archesporial or pollen-forming tissue.

“The anthers of type two are normal in appearance, but the pollen-mother-cells degenerate before pollen grains are formed.  A comparison of the degenerate pollen-mother-cells of this plant with normal pollen-mother-cells is given below:” 

[Illustration:  Sections of anthers of the Weschcke Hickory Carya ovata

Illustrations by Dr. McKay showing pollen degeneration in Weschcke hickory.]

This substantiates the conclusion that I had arrived at previous to this report, that this hickory is able to mature its nuts early in the fall by reason of not having to waste its energy in the production of pollen.  (There is only one other variety of hickory which I have grafted on bitternut which has proved unable to mature pollen and it is the Creager from Iowa.) I was immensely pleased to find that it responded very well to Bridgewater pollen, a high percentage