ae ee Cee OP ee ae) ad Be oe es ee ee ee ee ee ee ee ee Se eee ee ee ee Gee eee 
' 
112 MISSOURI BOTANICAL GARDEN. 
later dried and fell to the ground, hung everywhere from 
the branches. Much of this dried material hung on for 
weeks, and in maples nearly all summer. This phenomenon 
of holding on to the dead leaves, or parts of leaves, was 
extremely interesting. The killing effect of the freeze 
extended in some cases, as in Paulownia imperialis, into 
the previous year’s wood, and nearly always into the new 
shoots and foliar growth. The variation in its action is 
very well shown in Table I and II, in which the headings at 
the top of the columns are taken as questions, and 
answered for each of the species observed, by Y = yes; 
N=no or none; K =—killed; PK —partly killed; G= 
general or good. 
From this table we are able to formulate a few 
general opinions, but mainly the fact that a freeze in its 
action on vegetation does not always have the same effect on 
all plants. When we admit this fact then, we are obviously 
led to the conclusion that there may be all gradations of 
cause and effect, but that when the cause is the same, as 
is the case in any definite freeze, then the effect is differ- 
ent for each particular case. In the case of the freeze under 
consideration it has been possible to group the effects under 
five rather clearly defined sections. 
I. Those species for which complete immunity was 
recorded. 
Clethra alnifolia Magnolia stellata 
Cornus Mas Quercus imbricaria 
Cornus stolonifera Rhus copallina 
- Euonymus Sieboldiana Syringa persica 
Magnolia Kobus Syringa vulgaris 
II. Those in which the leaves were only partly frozen. 
Acer dasycarpum Euonymus atropurpureus 
Acer laetum rubrum Fagus sylvatica purpurea 
Acer platanoides Halesia tetraptera 
Acer saccharinum laciniatum Hamamelis virginiana 
Aesculus Hippocastanum Hydrangea paniculata 
Aesculus parviflora Hydrangea radiata 
Cornus Baileyi Ligustrum amurense 
Diervilla rosea Magnolia cordata 
