le
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 of the blooms treated with it
developing mature nuts. The results with the Kirtland pollen were almost
equally good, the poorest showing coming from those branches treated
with Beaver pollen on which only three mature nuts developed. (The
Beaver is presumed to be a hybrid between bitternut