50 BOOKS AND CURRENT LITERATURE 



ciation is also employed in a broader sense to include the two conso- 

 ciations and the mixed area. 



Each of the above named plant communities is a climax and repre- 

 sents, according to the author, a final stage of development. Similar 

 manifestations may be found which represent only earlier stages in 

 the development. For these the author has proposed a similar set of 

 terms. For the stage which will develop into an association he pro- 

 poses the term "associes;" for the consociation, "consocies;" and for 

 the society the term "socles;" and for the clan the term "colony;" 

 and for the plants which develop from a single parent the term "family." 

 The term "plant community" is now used by ecologists in a general 

 sense to apply to any unit of vegetation. 



The careful application of these terms will undoubtedly bring out 

 many conclusions with respect to vegetation which would not other- 

 wise be recorded, and to this extent they will greatly further the sub- 

 ject by forcing concrete expression of conclusions. They do not, how- 

 ever, insure the correctness of the conclusion. The distinction between 

 a society and a socies is debatable and difficult to draw; still an attempt 

 to make the distinction should lead to clearer thinking. Nor can the 

 the reviewer escape the feeling that the association as here distinguished 

 from the consociation does not clearly meet the conditions as found in 

 nature and that while it may be a most convenient means of reducing 

 the conditions of seeming chaos to a condition of order, a certain 

 amount of forcing is necessary. This feeling is strengthened by the 

 fact that conditions of soil and climate are more uniform over the 

 large stretches of pure stands than in the mixed areas lying between. 

 Clements' refers to the Artemesia-Sarcohatus association as the climax 

 association of the Great Basin, while Weaver (University of Nebraska 

 Studies, Vol. XVII, No. 1: 1-133, 1917) later refers to an Artemesia- 

 Atriplex association in the desert region of Washington. Both in- 

 stances are attempts to force the vegetation into the system proposed 

 by Clements. The conditions under which Artemesia grows are very 

 distinct from those of either Atriplcx or Sarcobatits. The plants are 

 found growing together only in areas where conditions are changing 

 rapidly or are locally very ununiform. Both cases represent com- 

 paratively narrow ecotones. It also seems unsafe to make the number 

 of species involved a criterion of the plant association. It would seem 

 more natural to find either a pure stand of one species as in the case 

 of sage brush or yellow pine or a mixture of two to many species such 

 as the grama-buffalo grass or Andropogon sod associations, of the 

 Plains and Prairie. 



