426 Hill . — Shidies in Seed Germination. 
seen at the base of the cotyledonary petiole— -but for some unknown 
reason, except in the single case mentioned, the cells of the plumular leaf 
appear to be unable to produce any adventitious outgrowths in the way 
of roots. 
To return now to the second cotyledon of the Cyclamen seedling. It 
has been shown that the normal single cotyledon shows marked differences 
from the plumular leaves when mutilated by removal of the lamina which 
affords a certain means of distinguishing the two organs. It becomes 
therefore a matter of interest to examine the behaviour of the second 
cotyledon under like conditions, more especially as additional evidence may 
thus be obtainable in support of the contention that the embryo of Cyclamen 
is truly dicotyledonous. 
From a number of seedlings in which the second cotyledon had been 
induced to develop, the laminae were removed, and in due course the response 
was exactly comparable to the traumatic reaction obtained with the first 
cotyledon, though, owing to the less robust character of the petiole, the 
percentage of successes was considerably smaller. From the apex of the 
petiole an outgrowth arises either on one or on both sides of the groove of 
its inner surface and develops to form a new assimilating organ as a flange 
or wing-like organ placed at right angles to the original lamina (PI. XX, 
Fig. 5, and Text-figs. 11, 12). 
Leaf cuttings of the second cotyledon have also been made and in the 
majority of cases roots have developed from the base of the petiole exactly 
as occurs with the first cotyledon ; such rooted cuttings have not, however, 
produced adventitious buds or developed a plumule. As in the case of the 
first cotyledon there was no formation of a callosity at the base of the 
petiole (Text-fig. 13). 
The leaves produced from the edges of the decapitated seedling 
tubers, being, as it may be assumed, ‘ cotyledonary ’ in character, were next 
tested to see whether they would respond to wounding in the same manner 
as do the first and second cotyledons, and it was of considerable interest to 
find that their response was quite similar. When put in as cuttings, roots 
were developed quickly from the base without a swelling being formed, but 
no formation of adventitious buds has so far been observed (Text-fig. 14). 
It may be that both with these adventitious leaves and with the second 
cotyledons adventitious buds might be formed if conditions should happen 
to be favourable. 
The laminae of these adventitiously produced leaves were also removed, 
and a new lamina was developed from the edge of the petiole near the apex, 
in precisely the same manner as new laminae are produced from the 
petioles of the mutilated cotyledons (Text-fig. 15). 
These experiments are of interest, since they tend to show that the 
adventitious leaves produced from the edge of the cut surface of the 
