296 



THE FORMATION 



senses, it is proposed to term this primary division of the formation, a con- 

 sociation, or better, a consocics. This term is applied only to an area char- 

 acterized by a facies, or less frequently, by two or more facies uniformly 

 commingled. The consocies of grassland are determined by grasses, those 

 of forests by trees, etc. From the different position of the facies in these 

 two types of vegetation such areas are readily seen at all times in the forest, 

 but they are often concealed in grassland by the tall-growing principal spe- 

 cies of the various aspects. When definite consocies are present, they are 

 often found to mingle where they touch, producing miniature transition 

 areas, and, very rarely, they sometimes leave gaps in which no facies appears. 



Fig. 77. Late (scrotinal) aspect of the alpine meadow, characterized 

 by Campanula petiolata, Rydbcrgia in fruit. 



The seasonal changes of a formation, which are called aspects, are indi- 

 cated by changes in composition or structure, which ordinarily correspond to 

 the three seasons, spring, summer, and autumn. The latter affect the facies 

 relatively little, especially those of woody vegetation, but they influence the 

 principal species profoundly, causing a grouping typical of each aspect. 

 For these areas controlled by principal species, but changing from aspect to 

 aspect, the term society is proposed. They are prominent features of the 

 majority of herbaceous formations, where they are often more striking than 

 the facies. In forests, they occur in the shrubby and herbaceous layers, and 



