THE SCOPE OF BOTANY. 667 



lar by those saplings which, develop from underground parts 

 often quite distant from the parent trunk ; and most of the higher 

 plants can be reproduced in cultivation by cuttings, slips, etc. 

 The sexual reproduction has been developed from simple forms in 

 low plants for example, the seaweeds to a state of complexity 

 among the flowering plants which is equal to that among the 

 higher animals. Though there are no superficial resemblances 

 between the sexual reproduction of animals and that of plants, 

 yet the processes are intrinsically the same. The differences are 

 mainly superficial, like those in the means of conveying the male 

 elements to the female elements. The male and female elements 

 in plants are very different from one another, just as in animals, 

 much more different from one another than these elements are 

 from the corresponding elements among animals. In the one 

 kingdom as in the other fertilization takes place when a male ele- 

 ment fuses with a female element. So much alike indeed are the 

 microscopic processes in the two kingdoms that much light has 

 been and still may be thrown upon the great general questions of 

 the influence of parents on offspring, of heredity, of descent, of 

 development, by the microscopic study of the phenomena of fer- 

 tilization and development among plants. There is, therefore, a 

 science of embryology cultivated by botanists which is of almost 

 equal value to man with the science of embryology cultivated by 

 zoologists. 



The microscopic study of the purely vegetative as distin- 

 guished from the reproductive parts of plants reveals certain 

 mechanical principles of structure which engineers are now just 

 beginning to follow in their buildings, especially those con- 

 structed of materials which in large masses resemble in physical 

 qualities those microscopic elements of which plant structures 

 are composed. We see that the stems of our native trees and 

 those of the palms and others of warmer climes are really frames 

 consisting of long, slender, light yet strong and elastic beams so 

 joined together that they form a structure capable of supporting 

 great weights in spite of the force of gravitation, and so but- 

 tressed at points of branching and where the aerial structures 

 spring from their strong foundations in the soil that they are able 

 to resist the really tremendous strains brought to bear upon them 

 by high winds. These principles of buttressing, of accurate bal- 

 ancing, of avoiding sharp angles by the substitution of curves, of 

 a light, elastic framework of great strength, which are common to 

 all the larger plants, we see employed in those buildings which 

 by reason of height, position, or purpose are exposed to great 

 strains. For example, there is more than a fancied resemblance 

 between the Eiffel Tower and the steel lighthouses of our coasts 

 to the buttressed, spreading bases of our elms. 



