Keegan : The Fades of our Forest Flora. 



7i 



this multum in parvo due to ? Whence all this massy con- 

 centration of slender boug-hs and miniature shoots, of small 

 and deeply-divided foliar organs ? 



Let me endeavour to explain. Roughly, the number of 

 -shoots and twigs that appear upon a tree is dependent on the 

 number of buds that burst and evolve to maturity. In all cases 

 a great many more buds are raised than what ever actually do 

 develop. In the axils of our leaves two buds arise, of which 

 the higher one in the upper and middle nodes of the branch 

 ■commonly bursts and develops all right, while the lower one 

 mostly remains latent. The feature to be elucidated is, there- 

 fore, the comparatively large number of buds that actually do 

 burst and expand ; because it is pretty evident, from what, has 

 been aforesaid, that the fewer of these organs that burst the less 

 numerous is likely to be the leaves, and. hence in our clime, with 

 its infinity of small leaves, it is essential, in order to produce 

 this latter effect, that a large number of buds be induced to 

 unfold at the appropriate time, i.e., in spring. Of course and 

 no doubt if all the buds produced and perfected in the previous 

 summer and autumn were to evolve in the ensuing spring, the 

 tree would die from exhaustion. A certain amount of restriction 

 is therefore indispensable. For instance, a Beech of ten years 

 old might have put forth only five branches, although its struc- 

 tural organisation would be quite capable of producing" nine 

 branches ; or it might actually have thrown off only about three 

 hundred shoots, whereas something over nineteen thousand 

 would represent its native organic competency in this respect. 



It is scarcely necessary to dwell at any length on the 

 principal means and org'anic contrivances whereby this abso- 

 lutely necessary restriction of the shoot-, twig-, and leaf- 

 formation of our trees is brought about. Inasmuch, however, 

 as this matter has been almost completely ignored by the 

 professorial compilers of British botanical text-books, a mere 

 enumeration may do no harm. The causes of the reduction and 

 final extermination of shoots, then, are these: — (1) An insufficient 

 illumination of the buds; (2) the capping of the twig by a flower- 

 bud or a fruit-bud ; (3) the decussate arrangement of twigs and 

 leaves ; (4) sympodial branching ; (5) cracking' and breaking oft 

 of branches already formed; (6) imperfect illumination of the 

 spray. Of these we need only refer to the first and last, viz., 

 the insufficient illumination of the buds and of the spray. It is 

 evident that in the case of a large-leaved tropical tree the buds 

 and portions of the branches which are seated beneath its 



J901 March i. 



