26 



LETTERS ON TREES. 



to make the theory itself clear and intelligible in all 

 its parts. 



3. Agreeably to this theory, as you may remember, 

 a tree is not what it is commonly believed, and what 

 it certainly appears to be, a single or an individual 

 plant. On the contrary, it is a collection— congeries, 

 or congregation of individual plants of the same species, 

 and is the production of a series of successive years. 

 It consists, when fully equipped at midsummer, partly 

 of living and growing plants, the growth of the cur- 

 rent year, and partly of the persistent dead remains 

 of the plants of former years. And of the individual 

 plants composing it, each lives only one year, reaches 

 its full size within the year, and, on dying at the close 

 of it, mostly disappears and passes away. Certain 

 parts, however, remain. These are the buds which 

 survive the winter, and the dead stems and roots which 

 are to serve the purposes as well of a soil as of frame- 

 work to the plants of the next and succeeding years. 

 And, accordingly, the production of the aggregate, 

 which makes up and constitutes the tree, is referable 

 to the living plants of each year growing parasitically 

 at the end of, and likewise either around or within, 

 the dead stems and roots of the plants of the previous 

 year. 



4. All this I stated in my first letter. I now advance 

 a step further and say, that the theory in question 

 forms but a part of a proposition in vegetable physi- 



