Roots 107 



root a plant possesses, for to do this one must measure 

 not only the main root, or roots, but the branches, root- 

 lets, and fibers as well ; and even then, the fringe of hairs 

 will have to be left altogether unreckoned. 



An oat or barley plant, for instance, has roots several 

 feet long; but when we say several feet, we merely mean 

 that they stretch several feet downwards through the soil. 

 Their real length, if the many roots are measured end to 

 end, branches and all, is a very different matter. A 

 barley-plant grown in a very small quantity of rich porous 

 soil, was found to have a total length of root of one hun- 

 dred and twenty-eight feet. This measurement included 

 the fibers, but not the hairs. In loose soil, such as this, 

 roots can make their way easily; but in closer soil, growth 

 is more difficult, and so slower, and a plant grown in soil 

 of the latter sort had roots only eighty feet long. Only 

 eighty feet; but both the eighty feet and the one hundred 

 and twenty-eight feet were packed into the fortieth part of 

 a cubic foot of soil, a quantity which would be contained 

 in a box between three and four inches square and equally 

 deep. 



Of course, if these roots had had their liberty they 

 would have been much less branched, and would have 

 spread much further. They would, so to say, have gone 

 much further ahead, without running up so many by- 

 paths. But being prisoners, they had to make the most 

 of what they had, and so explored most thoroughly the 

 small space at their command. Every one knows what a 

 mat of roots and fibers there will be when a plant is taken 

 out of a pot too small for it; such a mat that the earth is 

 often completely enveloped. 



Now, of course, it is not natural for a plant to grow in 



