654 DR JAMES STARK ON THE SHEDDING OF 
spring or at the close of summer; consequently each year’s growth can easily be 
traced in theramule. The cast ramules exhibit sometimes two, sometimes three, 
sometimes four seasons’ growth; and in one of the specimens figured, the growth 
of five seasons is seen. The great majority, however, show that they have only 
been three years upon the tree. These ramules are generally simple, but occa- 
sionally they are compound. Figs. 15, 16, 17, 18, and 19 illustrate the above. 
Wellingtonia (or Sequoia) gigantea.—Here ramules are cast off annually; 
this process continuing during October, November, and December. Figs. 20, 
21, and 22 are from impressions of some of the fallen ramules. Very much 
larger ones are thrown off, but it was found impossible to take impressions, 
because they were so brittle that even the gentlest handling caused all the 
smaller branchlets to become detached. I have as yet quite failed to trace the 
number of years these ramules remain attached to the tree before they are 
thrown off. 
It is thus seen that in six genera of Cupressineze, leafy twigs or ‘ ramules ” 
are annually cast off, and it seems probable that when the other genera belong- 
ing to that sub-order are examined they will be found to present the same 
peculiarity. 
The mechanism by which the ramule is thrown off appears to be strikingly 
similar to that by which the leaves of ordinary deciduous trees are shed. The 
ramule is attached to the branch by a joint or articulation, which, in so far as 
the bark-structures are concerned, is very similar to that which exists at the 
base of the leaf. The chief difference lies in the more pronouncedly woody 
characters of the fibro-vascular elements of the ramule. As the autumn 
-advances, the bark of the branch forms a fine corky layer under the point of 
adhesion of the ramule; while at the same time a change takes place in the 
woody structure, which seems to undergo a kind of ulcerative process which 
breaks up the tissue at the point of junction, so that it snaps at the slightest 
touch or even by the simple weight of ramule. When the ramule falls (as I 
have alreadystated regarding the Nootka-Sound Cypress) the whole bark surface 
to which it had adhered is seen to be perfectly healed, excepting the small round 
aperture in the centure through which the quill of wood passed. 
It appeared to me of interest to ascertain whether there was any essential 
difference between the ramules in the Cupressinez and the permanent shoots. 
For several years past, therefore, I have been making experiments to ascertain 
whether these ramules could be developed into permanent shoots by making 
cuttings take root and tracing what became of the ramules; and also by 
endeavouring to raise plants from pure ramules, which if left on the branches. 
would undoubtedly have been cast off as effete within the year. I have 
thoroughly succeeded in both of these attempts. Thuja occidentalis and Sequoia 
- sempervirens were found best adapted for making these experiments; but they 

