1921] STRAUSBAUGH—DORMANCY AND HARDINESS 353 
direct and definite proof that there is distinct relationship between 
the moisture content of the twig and its power to resist the action 
of frost, and that those trees whose new growth contains the largest 
percentage of water as winter approaches are in all probability the 
most tender.” He also believes that hardiness is a quality that 
can be affected by cultural methods. He says that “hardiness is 
evidently something more than an inherited tendency. It seems 
probable that it is a quality largely under the influence of the soil 
conditions as regards moisture and temperature in the late summer 
and autumn months, and probably these factors rather than the 
severity of the succeeding winter determine the tree’s immunity 
from frost. If in northern latitudes vegetative growth be early 
arrested and ripening of the new wood thus induced, either by 
artificial means (pruning and cover crops) or by a dry and cold 
autumn, varieties now considered tender might prove hardy.” 
There can be no doubt as to the effect of cultural methods upon 
the ability of certain plants to withstand low temperatures. This 
effect is shown by the work of BATCHELOR and REED (2), who 
found that one of the factors in the winter injury of the Persian 
walnut (Juglans regia) was winter drought. The injury referred 
to is a killing of the distal ends of the branches rather than that of 
the buds alone. Under certain conditions they were able to prevent 
winter injury by irrigating heavily late in the season, after matura- 
tion had been induced by withholding the water supply during the 
latter part of the summer. Their work shows a very evident 
relation between soil moisture and winter injury. 
In the introduction attention was called to the fact that dor- 
mancy occurs in widely varying degrees. The range extends from 
no dormancy at all to profound dormancy, with every degree of 
intergrading conditions. If in perennial woody plants there is a 
positive correlation between dormancy and hardiness, it follows 
that there must be a corresponding range of hardy conditions. 
If the forms under consideration chance to be closely related as to 
position in the series, or closely adjusted to the equilibrium of the 
external environment, it is easily conceivable that cultural methods 
may affect the relative degree of hardiness within certain limits. 
Such a case would seem to be exemplified by the Persian walnut 
