THE MATERIAL OUTGO OF PLANTS 355 



reappear in the ash, when the organic matter is burned away, as CaO, 

 MgO, etc. Moreover, certain mineral salts may be stored in the wails, 

 as silica often is; and these reappear as oxids in the ash. 



Fall of branches. In woody perennials the competition between 

 branches is so severe that many more die than survive. Thousands of 

 rudimentary branches (as buds) never develop at all, and other thousands, 

 after growing for a year or two, are outstripped by their more fortunately- 

 situated fellows, die, and drop off. The mortality is vastly greater than 

 is realized without close observation, such as was made on a volunteer 

 ' black cherry, and described in figurative language thus : 



The first year it made a straight shoot nineteen inches high, which producec 

 twenty-seven buds. It also sent out a branch eight inches long which bore twelve 

 buds. The little tree had, therefore, enlisted thirty-nine soldiers for the coming 

 conflict. The second year twenty of these buds did not grow. Nineteen of them 

 made an effort, and these produced three hundred and seventy buds. In two years 

 it made an effort, therefore, at four hundred and nine branches, but at the close of 

 the second year there were only twenty-seven branches upon the tree. At the close 

 of the third year the little tree should have produced about thirty-five hundred buds 

 or branch germs. It was next observed in July of its fourth year, when it stood 

 just eight feet high ; instead of having between three and four thousand branches, it 

 bore a total of two hundred and ninety-seven, and most of them were only weak 

 spurs from one to three inches long. It was plain that not more than twenty, at 

 the outside, of even this small number could long persist. The main stem or trunk 

 bore forty-three branches, of which only eleven had much life in them, and even 

 some of this number showed signs of weakness. In other words, in my little cherry 

 tree, standing alone and having things all its own way, only one bud out of every 

 hundred and seventy-five succeeded in making even a fair start towards a perma- 

 nent branch. And this struggle must have proceeded with greater severity as the 

 top became more complex, had I not put an end to its travail with the axe ! 

 BAILEY: Survival of the unlike, p. 88. 



Loss of bark. The constant flaking-off of bark, when the warping 

 due to wetting and drying loosens the outer portions, or the steady 

 weathering of the solid bark, occasions further losses of a relatively 

 inexpensive kind. As in some cases waste products accumulate in the 

 bark, this may be accounted one way by which the plant gets rid of 

 wastes. Bark also contains a very large percentage of ash. 



Fruits and seeds. Fruits and seeds are separated annually from the 

 body. These are loaded with surplus food for the embryo, and so consti- 

 tute a most expensive loss one that not infrequently distinctly impairs 

 the vitality of the plant. The intermittent bearing of orchard trees, 

 vines, etc., may herein find a partial explanation. 



