G48 



JOURNAL OF THE EOYAL HORTICULTURAL SOCIETY. 



importance than the presence of any particular one among them, and 

 there are so many influences crossing and neutralizing each other in 

 the life-history of any plant, that botanists are not agreed as to which 

 is the factor of greatest importance in controlling plant distribution. 



This paper tries to show how land may be classified with reasonable 

 accuracy by studying its natural vegetation as a whole and in relation 

 to all the local conditions. 



Natural vegetation is not only an expression of the present con- 

 ditions, but to some extent a record of conditions that have obtained 

 during a period of many years. In the character of the whole plant 

 cover, therefore, we have a record as stable as the most stable species 

 and as sensitive as the most exacting plant, and it is pointed out that, 

 as far as the conditions of growth are concerned, many native American 

 plants are far more exacting than the cultivated crop plants. The 

 investigations carried on on these lines at several places in the Great 

 Plains are here carefully described. 



The various groups or " associations " of plants were carefully 

 classified and recorded as belonging to the area in which they occurred, 

 and such physical data as soil-moisture, rain-fall, run-off, water- 

 penetration, and water-loss, and such disturbing factors as ploughing, 

 grazing, fires, parasitic fungi, etc., were noted in connexion with their 

 presence. The relations of such physical conditions to their accom- 

 panying orders of plant-life were considered, and general conclusions 

 were drawn as to the probable adaptability of the districts under 

 observation to certain cultivated crops.- — M. L. H. 



Corrigenda. 



Pp 127, 129. The Table of weatlier records for April is printed under Mardj 

 ' on p. 127 ; that for March under April on p. 129. These Tables (only; 

 should be transposed. 

 P. 135, line 13, for 50° read 5°. 



P. 394. The last sentence of the introduction to the Sweet Pea Report ha 

 been transposed from its position five lines earlier. The report should rea( 

 (commencing line 8) : " Several varieties were also commended on accoun 

 of their strong growth, and because of their non-burning qualities. The; 

 are indicated by the sign P below. These varieties "... etc 



