34 ANNUAL GROWTHS RECORDED 



the primary axis ; and the sum of the figures of the 

 ten columns marked L, of the secondary axes, or, 

 20+15+16+21+11+13+13+13+3+2=127, shows that 

 one hundred and twenty-seven leaves were put forth by 

 the ten secondary axes or branches ; therefore, the total 

 number of leaves which constructed the entire branch, was 

 127+28 = 155. 



If the reader will refer to the Table and then to the 

 Plate, he can form a true estimate as to the size of the 

 branch. The length of the primary axis is twenty-seven 

 inches and three lines, and of the largest secondary axis 

 fifteen inches: yet it is the leaf-labor of one hundred and 

 fifty-five leaves! The branch itself we have shown to be 

 only six years old. What then must be the immense num- 

 ber of leaves engaged in the construction of trees which put 

 forth thousands of such twigs, comparatively speaking, from 

 their immense spreading branches, which grow from one to 

 two hundred feet in height, and whose giant forms have 

 stood for hundreds and even thousands of years? Who can 

 estimate the quantity of leaf-surface spread abroad in the 

 atmosphere from the first commencement of germination, 

 and the amount of leaf-labor necessary to rear such vast, 

 noble, and enduring vegetable monuments ? " The Washing- 

 ton Elm, at Cambridge a tree of no extraordinary size 

 was some years ago estimated to produce a crop of seven 

 millions of leaves, exposing a surface of two hundred 

 thousand square feet, or about five acres of foliage."* 



Again referring to the Table and the engraving, we find 

 that the increase of leaf-surface each year, was as follows: 

 1853,5; 1854,9; 1855,25; 1856,30; 1857,41; 1858,44. 

 That is to say, in 1853 the branch put forth five leaves, in 

 1854, nine leaves, <fcc., &c. These numerical results are ob- 

 tained by adding together the figures under L, opposite the 

 years, across the columns. 



* " First Lessons in Botany and Vegetable Physiology," by Asa Gray, 

 1857. 



