2l8 BOTANY. 



many forms, as in the duck-weeds, it is a frond. While there 

 is great variation in the form and function of the members of 

 the plant body, they are reducible to a few fundamental mem- 

 bers. Some reduce these forms to three, the root, stem, and 

 leaf, while others to two, the root and shoot, which is perhaps 

 the better arrangement. Here the shoot is farther divided into 

 stem and leaf, the leaf being a lateral outgrowth of the stem. 



358. Synopsis of members of the plant in angiosperms. 



Root. 

 Higher plant. \ , g . 



Shoot. \ btem - 

 I I Leaf. 



' Foliage leaves. 



Perianth leaves. ] 



Spore-bearing leaves I 



... . J- Flower, 



with sporangia. ! 



(Sporangia sometimes i 



on shoot). 



359. The parts of the plant body as members or organs. — 



The members of the plant body can be considered from 

 several standpoints. We might study them from the standpoint 

 of physiology, when the members would be regarded as organs 

 for performing certain kinds of work. As organs for nutrition 

 the leaves serve a purpose in transpiration and in starch for- 

 mation. The roots and root hairs serve as organs for absorption 

 of food from the soil. The bright petals of flowers often serve 

 to attract insects which aid in cross-pollination. The stamens" 

 and pistils serve a purpose in the process of reproduction. The 

 stems serve as support for the plant, for the transport of food 

 materials, and for bearing the leaves and flowers. So in various 

 modifications of the members purposes of protection, support, 

 vegetative propagation, etc., are served. 



In this sense the members of the plant body might be studied 

 in Part I, in conjunction with the study of the means by which 

 plants obtain their food. 



From another standpoint we might consider the great variety 

 of form, and the numerous modifications, as expressions of the 

 forces of evolution, inheritance, relation to environment, etc. 

 (see Ecology). 



