HISTORICAL DEVELOPMENT OF BOTANY 213 



have Gray's manuals as our principal aids to a better knowledge 

 of the classification of our common wild flowering plants. Since, 

 however, a correct classification of any group of organisms, such 

 as oaks, grasses, or fishes, is based not only upon external char- 

 acters but upon details of structure and development as well, it 

 is quite obvious that we can never make a reliable classification 

 of any group of living things until we have a more or less 

 complete knowledge of the comparative structure and develop- 

 ment of the individual members of such a group. Such a knowl- 

 edge of the great groups of animals and plants which are now 

 classed together is not yet available, and classification, although 

 the oldest, is consequently a more or less artificial branch of 

 biological science to-day. 



Morphology. As the name indicates, morphology is the science 

 of the form of the animal or plant body ; but it has come to 

 include the structure and development, as well as the form, of 

 living organisms. It may include simply the study of the gen- 

 eral form, structure, and development of a single organism or 

 it may refer to a comparative study of the main organs, such 

 as leaves, stem, roots, and flowers, of a group of related organ- 

 isms. Applied to such organisms as pine trees and their allies, 

 it would comprehend the common conelike habit of pines and 

 the gross structure and form of their branches, leaves, roots, and 

 reproductive cones. These factors, taken together, determine the 

 characteristic form, appearance, and mode of reproduction of 

 members of the pine family. Since morphology has come to 

 include the structure and development as well as the form of 

 organisms and their parts, special terms are now used to desig- 

 nate the more detailed studies of structure and development 

 which have grown out of the older and grosser morphology. 



Anatomy. The term anatomy is usually applied to the more 

 general studies of the structure of the tissues, and organs of 

 both animals and plants. In plants anatomy is necessarily 

 microscopic, while in animals it includes the grosser observa- 

 tions of the organs and tissues which can be acquired by dis- 

 sections. Thus, the anatomy of a pine tree would include the 

 microscopic structure of sections of the trunk, leaves, branches, 



