644 THE STRUCTURE OF ECONOMIC PLANTS 



phloem strand. These parallel the course of the bundles and 

 are frequently interconnected by anastomoses and cross branches. 

 (Fig. 334, A.') 



Fig. 338. Transection of portion of stem showing bundle and medullary phloem, a part of 

 cortex is not shown, variety New York Special: ca, cambium; col, collenchyma; en, endo- 

 dermis; ep, epidermis; Ix d, lactiferous duct; m ph, medullary phloem; par, parenchyma; 

 /)f/, pericycle; ph, phloem; a^, xylem. 



Stomata occur in both epidermal surfaces, the frequency being 

 greater in the abaxial one. The epidermis is also characterized 

 by multicellular epidermal hairs which consist of a single or 

 double row of cells that are terminated by a capitate enlargement. 



( 



