1923] Proceedings of the Elisha Mitchell Society 39 



species at least ten in number, depends chiefly, so long as conditions 

 remain reasonably constant, upon the ages of the species in that 

 country, but may be enormously modified by the presence of barriers 

 such as seas, rivers, mountains, changes of climate from one region 

 to the next, or other ecological boundaries, and the like, also by the 

 action of man, and by other causes." 



In spite of the qualifications in the statement, many of which fol- 

 lowed extensive criticism, the principle has been found to hold good 

 in many countries, being especially well shown in Ceylon, New Zea- 

 land, and other islands. It has been possible on the basis of the 

 principle for the author to make many predictions, subsequently veri- 

 fied, as to the distribution of plants in many parts of the world, and 

 to draw interesting and important conclusions as to the history and 

 phylogeny of some plant species. 



The author is of the opinion that the rapid distribution of weeds 

 is a phenomenon following and consequent upon the disturbance of 

 natural conditions by man. In the absence of such disturbance, the 

 distribution of plants takes place slowly and with a certain uniform- 

 ity, so that it is possible to treat the phenomena of distribution with 

 mathematical precision. Such treatment may be expected to throw, 

 and has already thrown light on general problems of the first import- 

 ance, such as the development of phylogenetic lines and the origin 

 of species. 



Election of Officers: 



President — A. S. Wheeler. 



Vice-President — R. E. Coker. 



Perynayient Secretary — J. M. Bell. 



Recording Secretary and, Treasurer — H. R. Totten. 



Editorial Committee — W. C. Coker, Chairman ; J. M. Bell, Collier 



Cobb. 



H. R. Totten, Recording Secretary. 



