DEVELOPMENT OF ROOT SYSTEMS UNDER DUNE 



CONDITIONS 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 250 



W. G. Waterman 



(with seventeen figures) 



The attention of the writer was first attracted to this subject 

 by the lack of knowledge in regard to the causes of the development 

 and consequent extension of root systems.^ This seemed the more 

 surprising because this knowledge is important, not only from a 

 theoretical standpoint, but also because of its bearing on the prac- 

 tical activities of plant production. All of the responses of plants 

 to soil conditions, and some of those to atmosphere, are closely con- 

 nected with the condition of their root systems, but in the past both 

 botanists and agriculturists in the main have been satisfied to 

 interpret results by observation of the shoots only. It is evident 

 that in all cases where the chemical and ph3^sical Content of the 

 soil is not absolutely uniform, accurate interpretation of results 

 must take into consideration the extension and general condition 

 of the roots. 



Recognizing the practical difficulties of root observations, a 

 locality was chosen in which the character of the soil and the scat- 

 tered stand of the plants would make it possible to observe com- 

 plete root systems under natural conditions. It was soon found 

 that the distribution of nutrient material was also an easily observed 

 and very significant factor in this locality. The region also proved 

 to have great geological and synecological interest, and since it has 

 been described rather fully (44) elsewhere, it will be treated only 

 briefly here. 



In the figures the root systems are arranged as nearly as possible 

 in the natural position in a vertical plane. A 10 cm. scale was the 



' In this study the term "development" will be applied to the process of increase 

 in size and branching of the roots, "extension" will refer to the size of the system, and 

 "distribution" to the relative position of the system and its parts in the soil. 



Botanical Gazette, vol. 681 [22 



