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THE POPULAR SCIENCE MONTHLY 



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Fig. 2. Roots of Quercus lobata Growing by a Stkeam in Lake County. Owing 

 to the washing away of the bank the tree has lost a portion of its former support and 

 has leaned toward the streamway. The generalized character of the root system is 

 fairly well shown. 



the usual type, in that there is large development of the tap-root, from 

 which extend at various depths large laterals in comparatively large 

 numbers. The secondary roots may also penetrate fairly deep, although 

 occasionally they lie near the surface also. In large specimens, super- 

 ficial roots as long as 70 feet have been observed. Secondary roots 

 usually branch relatively little. In a word, the root-system of the 

 roble oak is especially well adjusted to take advantage of the more 

 deeply-lying soil moisture, while at the same time the more superficially 

 placed roots can absorb water from the more superficial soil layers. As 

 will be shown below, the root habit of the plant is one well calculated 

 to close adjustment with the peculiar habitat frequented by the species. 



Quercus agri folia 



■ The root-system of the encina oak is characterized by an especially 

 well-developed superficial portion, which consists of numerous relatively 

 short and relatively slender roots, which are placed, for the most part, 

 within three feet of the surface of the soil. There are also more deeply 

 penetrating roots, but these are relatively few in number. In young 



