March 20, 1903.] 



SCIENCE. 



455 



ous public entertainments which had been 

 arranged by the American Association, and 

 in addition two notable courtesies were 

 extended to the visiting members of the 

 society by botanists of Washington — the 

 first, a charming dinner at the Hotel Bar- 

 ton, given to the visiting members of the 

 society and their wives by the Washington 

 members and their wives on Tuesday even- 

 ing, and a reception later the same evening 

 given to all the visiting botanists by the 

 Botanical Society of Washington. 



The address of the president. Professor 

 Volney M. Spalding, dealt with 'The Rise 

 and Progress of Ecology,' and was deliv- 

 ered after the dinner at the Hotel Barton, 

 ^t is believed to be the first presidential 

 address to deal with this subject. It was 

 published in full in this journal for Feb- 

 ruary 6. 



The society voted to extend its warmest 

 thanks to the authorities of Columbian 

 University, to its members resident in 

 Washington and to the Botanical Society 

 of Washington, for the many courtesies 

 which had contributed to make the meet- 

 ing so successful and enjoyable. 



Following are abstracts of the papers 

 actually presented in full before the society 

 and thrown open for discussion, excluding 

 those offered by title. The abstracts are 

 by the authors. Certain papers appear 

 by members of the new Association of 

 Botanists of the Central States, the ses- 

 sions being to some extent joint ones with 

 that association. 



A Discussion of Mendel's Law and its 

 Bearings: Professor L. H. Bailey, Cor- 

 nell University, and Dr. Hekbeet J. 

 Webbee, Department of Agriculture. 

 Professor Bailey's paper is published 

 above. It is expected that Dr. Webber's 

 paper will also be published in this journal. 



The Early Boot Development of Tree 

 Seedlings, an Important Factor in their 

 Local Distribution: Professor J. W. 

 TouMEY, Yale Forest School. 

 A series of twenty slides were shown of 

 the initial root systems of various root 

 types of seedlings of American trees, pho- 

 tographed in various stages of germina- 

 tion, and at different later periods until the 

 species had grown well- developed initial 

 root systems. All of the seedlings were 

 grown at approximately the same time and 

 under the same soil and atmospheric con- 

 ditions. 



From the study of the root systems of 

 the various species, it appeared that the 

 form of the initial root systems of the trees 

 studied is surprisingly constant for the 

 same species. In other words, there is aii 

 inherent tendency for each species to pro- 

 duce an initial root system that takes a 

 definite form and direction. Early in the 

 life of the seedling, this initial root sys- 

 tem becomes more or less modified by its 

 environment, particularly by the moisture 

 and other soil factors. It was shown that 

 there are great differences in the different 

 species studied in the plasticity of the ini- 

 tial root system; that is, in the rapid and 

 marked changes from its initial form and 

 characteristics under the influence of en- 

 vironment. In some of the species shown, 

 as in, many hickories and oaks, the initial 

 root system has remarkable fixity. The 

 general form of the initial root persists, 

 no matter upon what soil the species grows. 

 It was pointed out that the species which 

 show but little plasticity in the initial root 

 system under the infiuenee of environment, 

 do not readily adapt themselves to variable 

 soil moisture conditions. 



In others of the species shown the initial 

 root system is extremely plastic, rapidly 

 changing under environmental influence, 

 as illustrated in the red maple. In this 

 species the initial root system consists of 



