bacterial growth developed from the vascular system. From these field
and laboratory studies, it was concluded that the wilting and stunting
were not produced by a plant pathogen. Since the affected plants in the
field were all confined to the area adjacent to black walnut trees, and
the fact that it had been shown that the bark of this tree does produce
a substance that is toxic to certain plants, it was concluded by
circumstantial evidence alone that the wilting possibly was due to black
walnut toxicity or antagonism of some sort.

In August of 1942, studies were made on wilted and stunted cabbage
plants growing in a semicircle on one side of a field adjacent to a
walnut tree (Fig. 1). The field was located near Hall, New York, in a
region known to be infested with cabbage yellows. From a distance, the
affected plants appeared to have yellows, but upon close study, it was
found that they were merely wilted and stunted and did not show the
other typical symptoms of the yellows disease. The root systems of
wilted plants did not show the presence of club root or black rot
infection. The plants in the field were all of one variety and came from
the same seed bed. Microscopic studies and attempts to culture a fungus
from the vascular bundles of affected plants showed the absence of any
fungus that might have caused, the disease. Since the affected plants
showed no symptoms of known cabbage diseases and as they were growing
in a semicircle adjacent to a walnut tree, it was concluded that the
presence of the root system of this tree might have been the cause of
the trouble.

[Illustration: Fig. 1. Wilted and stunted cabbage plants growing in a
semicircle adjacent to a black walnut tree. Note large, healthy plants
in foreground, side and background about a semicircle of smaller, wilted
plants, growing in an area affected by the root system of the black
walnut tree.]

These two instances of wilting and stunting of plants in the vicinity of
walnut trees give further circumstantial evidence that the trouble might
have been caused by the toxicity or antagonism of black walnut roots.
Detailed experiments with the plants in question would have to be run to
prove this assumption.

Preliminary Studies on Catkin Forcing and Pollen Storage of Corylus and
Juglans

L. G. COX, _Cornell University_

Methods of collecting and storing pollen are of great interest to those
engaged in plant breeding. Very little reliable informa