So far I have made only temporary preparations
of the crushed anthers in stain but careful study of these mounts
discloses no sign of pollen grains or mother cells, so we may
tentatively conclude that no pollen is produced by the tree; in
other words it is male-sterile. The stage at which degeneration of
the pollen-forming tissue occurs in the anthers and its nature will
have to be determined by means of a longer and more elaborate
technique and I will let you know what we find as soon as the
results are available. It may be that pollen-mother-cells are not
even formed in the anthers; the small size of these structures and
their more or less shriveled appearance lead me to believe that
this may be the case.
"So far as I know there is no instance among nut species comparable
to that outlined above. We have two or three cases of male
sterility in chestnut but in these no stamens are formed in the
individual staminate flower. In one of the hybrid walnuts that I
reported on at the Hershey convention, imperfect pollen grains are
formed in the anthers but the latter structures never open, so no
pollen is shed.
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