352 BOTANICAL GAZETTE [MAY 
Discussion 
In recent years the horticulturists of the northern United States 
and Canada have been greatly interested in the breeding of hardy 
fruits capable of resisting the low temperatures of this latitude. 
One of the difficulties met with in this work has been the amount 
of time required to test new seedlings for hardiness. Various 
attempts have been made to discover some means of detecting 
hardiness by direct observation at an early period in the develop- 
ment of the seedling. 
BEacH and ALLEN (3) made a rather extensive series of micro- 
scopical, mechanical, and specific gravity tests of apple twigs to 
ascertain whether “the hardiness of a tree could be determined 
while it was still in the nursery.” They concluded that “from the 
practical point of view as yet it is impossible to name any one test 
by which the degree of constitutional hardiness of a seedling apple 
may be foretold.” This work, however, has revealed some very 
interesting and suggestive facts that may have a fundamental 
value in the physiological study of hardiness. Among other things 
they found that “the hardier varieties on the average had a slightly 
lower moisture content than the more tender varieties,” and that 
“this difference is more marked during the growing season.” 
They state that this “difference in water content can be explained 
partly at least by the fact that the more tender sorts evaporate 
water more rapidly than do the hardy varieties. Freezing tends to 
dry the twig out, and after a period of very cold weather the twigs 
of the hardy varieties are generally found to contain the most 
moisture.” 
JounsTON (7) found that “‘as the season advances the difference 
between the water content of fruit buds of the Elberta and Greens- 
boro peach becomes more marked, the values for the Elberta being 
the greater.’’ Since the Greensboro peach is considered more 
hardy than the Elberta, the inference is that the more tender buds 
have the highest moisture content. In these determinations only 
10 buds were used in a sample, and it would seem that larger 
amounts of the tissue might give more reliable results. 
Suutt (11) found the moisture content of apple twigs of tender 
varieties higher than that of hardy twigs. He stated “that we have 
