L28 THE AMERICAN BOTANIST 



rich and varied conditions, whether by immigration or in- 

 digenous development, may be safely included among those 

 conditions. 



Is it not reasonable to suppose that the appearance of a 

 great body of herbaceous vegetation just at this time was one 

 of these conditions? This would affect directly the develop- 

 ment of all herbivorous types and indirectly of many others. 

 In the evolution of the tooth of the herbivora, indeed, we can 

 trace the change from a sharply cusped type suitable for chew- 

 ing tough leaves and twigs to the modern flat condition which 

 is capable of dealing only with the softer herbaceous tissues. 



Far more important, however, is the part which the herb 

 has played in the development of human civilization. Primi- 

 tive man seems to have been mainly arboreal in his habits, or 

 at least primarily a forest dweller, and the wood, bark, and 

 fruit of trees and shrubs were of supreme importance to him 

 as sources of shelter, fuel, implements, clothing and food. One 

 of his first steps from this barbarism toward civilization was 

 to enter the open and begin the practice of agriculture. Those 

 plants which most commended themselves to the earliest tillers 

 of the soil were probably not the slow-growing trees and 

 shrubs, but rather the herbs, since the rapidity with which they 

 grow and reach maturity makes possible their culture even 

 among such roving tribes as were our North American 

 Indians. Only as man acquired a settled place of abode and a 

 more permanent form of society could he begin the culture of 

 woody plants in orchard and vineyard; and it is only in very 

 recent times that agriculture has extended beyond these fruit 

 bearing trees and shrubs and, in the form of forestry, has 

 begun to treat the timber trees, themselves, as a crop to be 

 cultivated. 



The marked superiority of the herb in ease of agricultural 

 manipulation, together with the wide variety of uses of root, 

 stem, leaf, and fruit, have given it an increasingly high place 



