258 



BOTANY: PRINCIPLES AND PROBLEMS 



complete, our systems of classification will grow more accurate 

 and useful. 



Groups within Groups. — Plant classification is far more com- 

 plex, however, than a mere segregation of individuals into a 

 series of distinct groups, for each group is further subdivided 

 into smaller ones and each of these, in turn, into others still 



D E 



Fig. 140. — Species belonging to the same genus. Six species of maple (Acer) 

 represented by leaf and fruit. Each species is readily distinguishable from the 

 rest by its own individual peculiarities, but in all the species the fundamental 

 characteristics of the maple genus are evident. A, Acer Pennsyhanicum. B, 

 A. platanoides. C, A. spicatum. D, A. rubrum. E, A. saccharinum. F, A. 

 saccharum. 



smaller. This system of "groups within groups" is familiar 

 in methods of classifying all sorts of objects. An army, for 

 example, has a definite system of organization or classification, 

 whereby it is separated into a series of large groups, or divisions. 

 Each division, in turn, is made up of brigades; each brigade, of 

 regiments; each regiment, of battalions; each battalion, of com- 

 panies; each company, of platoons; and each platoon, of squads. 

 In this way every soldier occupies a definite and particular place 



