36 EASY LESSONS IN VEGETABLE BIOLOGY. 



tissues and vessels, other smaller groups are found, 

 with receptacles formed by passages between the 

 cells. According to -the nature of the substance 

 secreted these spaces are called oil-passages, resin- 

 passages, camphor-glands, resin-glands, etc. The 

 term nectaries, or honey-glands, is given to any 

 part of a flower which secretes honey or sugary 

 fluid. 



6. The first independent tissue formed in flowering 

 plants by the union of cells is the epidermis or skin. 

 The outer layer of epidermal cells is transformed into 

 a thin, structureless membrane called the cuticle. 

 The form of the cells varies in different plants, but 

 they are usually flat or tubular, but sometimes pro- 

 jecting like little knobs or bladders, which gives a 

 velvety or glistening appearance to the leaf or flower. 



Among the epider- 

 mic cells are found 

 pores, each of which 

 is called a stoma, or 

 mouth. (Plural, sto- 

 mata.) These are in- 

 closed by two or four 

 cells, which are cres- 

 cent-shaped, and dis- 

 tinguished from other 

 . 12. epidermal cells by 



their smaller size and by containing chlorophyll. 



