114 MISSOURI BOTANICAL GARDEN. 
Rosa rugosa Tsuga canadensis 
Sassafras officinalis Vitis vinifera. 
Taxus baccata 
SECTION I. 
To the first may be added another as a result of this 
year’s (1911) observations, namely Lonicera involucrata, 
which because of its behavior toward a frost of the present 
year is placed in the same category. ‘The first in the list 
was the only plant that had not started and so was unaffected 
and was placed here. While the leaves of the plants 
recorded in this section were apparently frozen, if we may 
judge from outward appearances, still they did not show 
any after effects as were observed to appear in the second 
section. So that on this evidence alone they have been 
placed in the list of immune varieties, although it is not 
taken that they were not frozen. No notes of any peculi- 
arities as to lateness of flowering, or early falling of leaves, 
ete., were taken later in the season, as will be evidenced 
in the resultant descriptions of the later sections. 
SECTION II. 
The enumeration of the species in the second section 
includes all those plants whose leaves, several weeks after 
the frost, showed, by the appearance of dried and withered 
parts, that sections had been killed as a direct or indirect 
result of the freeze. In nearly all cases the parts of the 
leaves took on a dried-up, rusty appearance, but in the 
case of Cornus Baileyi, the parts affected were red or black. 
In Acer saccharinum laciniatum the frozen parts dried up 
and in a few days were broken off by the wind, and only 
by a close observation could the effect of the freeze be ascer- 
tained, but in Acer platanoides and Acer dasycarpum the 
dried portions persisted, and during the summer it was 
possible to distinguish easily the frozen and unfrozen por- 
tions of the leaves. By this means it was easily seen from 
the maples and buckeyes that the major part of the damage 
occurred on the northwest and north sides of the trees, 
