THE STRUCTURAL CHARACTERISTICS OF THE COMMUNITY 29 



meadow communities 1 or 4 sq. m.). Let all the species be noted with 

 quantity or coverage, sociability, etc. Then double the size of the 

 sample plot and add to the first list the additional species included. 

 Then within the same type of uniform vegetation select a larger area 

 (16, 32, 50, or 100 sq. m.) so as to include the previous sample plots. 

 The study of this area will be found relatively simple, since usually but 

 few species will be added to the list. Any variations in the quantity, 

 sociability, etc., of any species of the first small sample plot should be 

 noted. It finally remains to note the species present in the stand 



Fig. 11. — A sharply delimited stand of the Polytrichum sexangulare association on a 

 snow pocket in the Bernina Alps at 2,450 m. {Photo by Klika.) 



outside the sample area. By this procedure two or more exactly 

 delimited areas of different sizes have been analyzed in the shortest 

 possible time, and at the same time a complete list of the species of the 

 uniform community has been obtained. The sample plots are best 

 square, or at least rectangular (Fig. 35). Communities arranged in 

 mosaic fashion, as in mountains and moors, must be worked by means 

 of a measuring line (Fig. 11). The shape of the sample plot will often 

 be irregular. If the sample areas are dotted with fragments of "for- 

 eign" vegetation, or if a terrace-like structure prevails, or if the 

 vegetation is interrupted by scattered rocks or by breaks in the sod, an 

 approxim_ate estim_ate of the extent of the homogeneous sample plots 

 must suffice. In any case the total area of the uniform stand and the 



