374 BOTANICAL GAZETTE [way 
spur shoot elongating, much after the fashion of the cycad stem, 
enough to accommodate each new set of leaves. The “spurs” 
in these forms may attain a length of an inch or more on the older 
branches; they gradually become shorter toward the younger 
parts, and on the season’s growth primordial leaves alone may be 
present. These persist in Cedrus for two to three years. The 
occurrence of these primordial leaves on the season’s growth are 
a contrast to the condition in the pines, where only scale leaves are 
normally produced. In Cedrus the fascicled leaves themselves 
persist for two to five years, while in Larix and Pseudolarix they 
are shed annually. In the pines they are indefinitely persistent, 
falling with the spur. Undoubtedly the persistent habit is the 
ancestral one for the conifers, having been overcome in two ways, 
by the deciduous leaf and by the deciduous branch, as the writer 
has tried to show in a recent article on the Araucarineae (27). 
The spur shoots of the three genera referred to, in addition to 
having the power of making a short yearly increase in length, have 
also the power to a marked degree of forming ordinary branches 
as occasion arises. The main axis may originate from a spur shoot, 
usually the terminal one, but if this is injured, any of the proximals 
may assume its function. Lateral branches also arise normally 
from spur shoots, especially from the younger ones. When, 
however, a branch is injured, they may arise from old spurs. The 
spur shoot of these three genera retain to a marked degree the 
power of branch formation. It remains, however, to a large extent’ 
latent unless called into activity by the needs of the plant. This 
dual power of the spur shoot either to produce a branch or to con- 
tinue the growth of the fascicle as such is an indication of the genetic 
relationship of the branch and spur shoot. One would scarcely 
expect such a feature in the pines, where ordinarily in the mature 
condition not even a rudiment of a bud can be discerned amid 
the closely set needles of the fascicle, and where, too, only the one 
set of leaves is produced and the axis neither increases in length 
nor in diameter after it has formed these. 
On the contrary, however, proliferating spur shoots similar to 
those in the other genera are of very general occurrence In 1 
pines. They do not occur so abundantly nor so normally as 
