202 GOEBEL: REGENERATION IN PLANTS 
The one exception to the above established by Hildebrandt, 
Winkler and others is the case of first leaves of the seedlings of 
Cyclamen Persicum. When one removes the leaf-blades in this 
plant there develop to the right and left of the petiole new blades. 
But in this case also, as I think I proved, there is only a develop- 
ment of latent rudiments. From the point of view of embryology, 
the leaf-stalk is a part of the leaf-primordium, in which the devel- 
opment of the leaf-blade is arrested. This condition of arrest is 
by no means so well established in the seedling as it is in later 
stages, and consequently it can be overcome. When the blades 
are removed from leaves in older plants these organs die without 
forming new blades. 
Similar conclusions were arrived at in all cases in which a 
critical examination was made. The phenomena of regeneration: 
in leaves, as described in the literature of the subject, will not bear 
careful examination. On the other hand, it can be shown that 
seedlings often possess a greater capacity for the formation of new 
organs than older plants. Not a few seedlings develop adventi- 
tious shoots on the hypocotyl even without being wounded. Such 
shoots have also been seen on the leaves of young plantlets of 
Lycopodium inundatum, but not on those of older plants. 
3. The character of the organ constructed depends upon the 
condition of the plant at the time regeneration ensued. _ Illustra- 
tions of this fact are quite as apparent in the lower as in the higher 
plants. The fungi may be cited first. From investigations by 
Van Tieghem and Brefeld we know that when, for example, the 
pileus of certain agarics is cut off, there is a regeneration from the 
stalk, not of a new pileus, but of one or more complete fruiting 
bodies. We see here that a direct restoration of the part that has 
been lost does not take place, but the new organ is dependent 
upon the condition of the plant, in that as a result of the wound, 
the mycelium proceeds immediately to build up a new fruiting 
body, and does not go through a longer vegetative period. 
It is to be remembered that the dependence of the formation of 
organs upon external conditions is much greater in fungi than in 
the higher plants. If the sporangium is removed from the fruit- 
ing hypha of Phycomyces there is developed a new fruiting hypha 
from the stalk of the old one. But when regeneration takes 
