HORSETAILS 87 



three to four angled. These stems perform the work of 

 photosynthesis because of the presence of chlorophyll and 

 innumerable stomata which occur in the grooves of the inter- 



FIG. 47. Equistacece. Two fertile strobile-bearing steins of Equisetum 

 arvense and between them is a young sterile shoot. To the right, a fully 

 developed sterile shoot showing at the base the rhizome; at 4, internode; 

 5, node; 6, whorl of branches. 



nodes. The growth of the main stem is apical and this growth 

 continues until fall in this latitude. The sheaths surrounding 

 the branches are greatly reduced and have acuminate points. 



