114 HISTOLOGICAL BOTANY. 



cuticularized. When roots or stems grow much in thick- 

 ness, the epidermis is usually ruptured and a new skin is 

 formed from the cortical fundamental tissue. 



SUMMARY. 



Tissues are those combinations of cells which are produced by cell- 

 division and united to each other from the beginning of their existence. 



The parenchyma is a tissue composed of parenchymatous cells. 



The prosenchyma is a tissue composed of prosenchymatous cells. 



The vascular tissue is one composed of vascular cells. 



The soft parenchyma is a tissue composed of soft parenchymatous cells. 



The hard parenchyma is a tissue composed of hard parenchymatous cells. 



The bast prosenchyma is a tissue composed of soft flexible prosenchyma- 

 tous cells. 



The woody prosenchyma is a tissue composed of hard lignified prosenchy- 

 matous cells. 



Bast vessels are those composed of soft vascular cells. 



Woody vessels are those composed of hard vascular cells. 



Tissue-systems are aggregations of elementary tissues forming a definite 

 portion of the plant-body. 



The epidermal system forms the outer skin of the plant-body. 



The epidermis is a membrane consisting of one or more layers of 

 parenchymatous cells. 



Stomata are the openings through the epidermis. 



Hairs are the protuberances on the surface of the epidermis. 



The fundamental system is that group of tissues which is situated within 

 the epidermal system and encloses the fibrovascular system. 



The fibrovascular bundle is a band chiefly composed of vessels and 

 prosenchyma. 



The xylem is the hard portion of the fibrovascular bundle. 



The phloem is the soft portion of the fibrovascular bundle. 



The fibrovascular system is composed of fibrovascular bundles. 



