Growth and Structure of the Wood of Larix. 637 
somewhat crushed by the next year’s growth, and their general appearance 
was of cells just cut off from the cambium, and which consequently had not 
yet lost their prismatic form or gained a thicker cell-wall. A few yards off 
from this tree was another Japanese Larch of the same age, but which 
showed no external traces of injury from the drought of 1911. It showed, 
however, outside the normal autumn wood for that year, a thin-walled zone 
of flattened cells similar to that just described in the other tree, but with 
rather thicker walls and not at all crushed. 
It seems, then, that in both these trees there had been a check to the 
autumn wood formation, followed by renewed growth. In the case of the 
first tree, which had lost the help of its terminal shoots, there was perhaps 
not enough food-material for a proper thickening of the cells then formed. 
But in the second example the shoots were all still able to function, and so 
the cells could be better thickened and might have been almost normal if 
the approach of the winter had not checked their further development. 
Investigations were also made in Kent upon a twenty-year-old larch 
tree which in September, 1912, was bearing a second flush of leaves on some 
of its spur shoots while other parts of the tree were still dark green, having 
retained the needles put forth in the spring. This second flush was 
especially noticeable on the spur shoots of the branches whose terminal bud 
had been killed in the preceding year. In none of the branches investi- 
gated, whether bearing a second flush or not, was there anything abnormal 
in the ring of 1912. But as the formation of autumn wood had set in 
before this second flush of leaves was fully grown, there should have been 
already induced by them some beginnings of a second thin-walled zone if 
such, as Strasburger suggested, were the natural consequence of a second 
leafing. Traces of such a zone, however, were found in the ring of 19 11, 
both in branches whose terminations had been injured that same year and 
also in those which were continued on unharmed into the shoot of 1912. 
The inference is that a zone of thin-walled cells outside the autumn wood 
is not caused by a second flush of leaves, but rather by inferior nutrition 
consequent upon unfavourable conditions of growth, such as were of common 
occurrence during the drought of 19 11. The Japanese Larches from Oxford 
support the same general conclusion. 
It must be admitted that the extreme youth of the only branches 
of this Kentish tree that were in fit condition for such comparisons detracts 
somewhat from the value of the conclusions obtained from them, and 
a similar reason lessens the importance of the two seven-year-old Japanese 
Larches. For in young trees and branches the formation of autumn wood 
frequently tends to be abnormal and deficient in thickening of its cell-walls, 1 
or marked by the bands of mechanical tissue already referred to, the 
so-called ‘ Druckzonen ’ 2 which may appear in the spring wood. But 
1 Cp. foot-note on next page. 2 Cp. Schwarz, p. 237. 
