167 



bare. It thus happens that the leaves are arranged as previously- 

 stated in interrupted groups. 



How many years constitute the life limit of the average rhodo- 

 dendron ? I put this question to myself many times as I walked 

 among these shrubs, and found for reasons which will presently 

 appear, that in the end I was unable to answer it satisfactorily. It 

 should be observed that this is very different from asking the age 

 of a branch, a thing which can very readily be estimated. For 

 determining the latter I have selected a representative branch of 

 an average shrub in which I was able to distinguish twenty- 

 eight yearly increments to its length, and thirty-one annual rings 

 of growth. From its position in relation to the other branches 

 I thought it to be at least one of the first to develop, if it was 

 not the primary stem, a fact I was unable to determine. Thus, 

 that branch was at least thirty years old, whatever may have 

 been the age of the portion from which it sprang. 



One is struck by the rarity of dead rhododendrons. I have 

 seen very few, and upon investigating the probable cause of 

 death of these, I always found it due to some catastrophe as the 

 washing away of the soil. Whether the rhododendron as a 

 plant rarely dies, the twigs and branches do, and the avoidance 

 of death by the entire plant is brought about, as will presently be 

 seen, by the development of adventitious buds. 



The duration of the life of a branch naturally depends on that 

 of the branchlets into which it is ultimately subdivided, and the 

 life limit of these in turn, hangs partly at least on a proper bal- 

 ance between the production of flowers and of leaves, and possi- 

 bly also to some degree on the length of the branch itself. 



In order to carry on the life of the branch any twig must pro- 

 duce each season at least one leaf bud, whether it gives rise to 

 flowers or not. Thus when flowers are also formed, the branch- 

 let has a double burden. Now it happens when the branches 

 are relatively long, that the vegetative (axillary buds) may not 

 develop, the flower bud only doing so, and therefore the death of 

 the twig follows with the ripening of the fruit. 



Whether both flower and leaf buds develop the same season on 

 the same twig depends apparently on the presence of suitable and 



