146 



for example, next to that of seasonal changes and movements 

 and responses, as well as to interrelations and distribution. 



The rectangular spaces left blank are those in which no laws 

 can be placed. For example, we can hardly conceive of the 

 nutrition of plant associations, or the geographical distribution 

 of cells. Spaces occupied only by interrogation points are 

 those in which there seem to be a few laws, but not enough to 

 have received a special name as yet. 



The last four or five columns should each be regarded as made 

 up of a multitude of smaller ones, corresponding to the different 

 kinds of tissues, plants, etc. Organs can be subdivided twice, 

 first into kinds of organs, and then into different forms of each 

 kind. Plants may be classified either by their supposed phylo- 

 genetic relationships, as in taxonomy, or by structure and 

 adaptations (this sometimes called ecological classification), or 

 in various other ways. For the taxonomic subdivisions there 

 are numerous minor "-ologies," such as mycology, bryology, 

 agrostology, and even batology and ionology; and for the struc- 

 tural subdivisions there are a few terms, of which dendrology is 

 probably the most familiar. 



Some of the horizontal rows, especially the last two, can be 

 similarly subdivided. The subdivisions of ecology are the 

 various environmental factors, and those of geography the 

 divisions of the earth's surface; and each of these systems may 

 be arranged in more than one way. 



In studying any portion of the field we may proceed either by 

 rows or by columns. For example, most ecological treatises use 

 the environmental factors for the primary subdivisions, and 

 consider the effect of each one separately on organs, plants, etc. 

 But the Chicago text-book, published about two years ago, 

 considers the organs first, and then the relation of each to different 

 environmental factors. Each method of course has its advan- 

 tages. 



In a general way this table might be said to indicate the order 

 of historical development of the sciences named. If such a 

 table had been prepared in the time of Linnaeus it would prob- 

 ably have lacked most of the lower half. The last column and 



