48 



Principles of Plant Culture. 



used by the plant are not taken in to the same extent as 

 those that are needed, because their equal distribution is 

 less disturbed. 



The distribution of soluble matter in the plant is also 

 promoted by transpiration (75). 



Section IV. The Inner Steuctuee op the Plantlet 



Thus far, we have considered the plantlet mainly from 

 the outside. Before going farther, it is well to learn also 

 something of its inner structure. We have seen that all 

 parts of the i)lant are made up of cells (12) and that 

 these cells differ in form and ofi&ce in the different parts. 

 The cells of the leaf, for example, are different in shape 

 and in the use they serve to the plant, from those of the 

 stem, flower or fruit. 



65. The Epidermis (ep'-i- 

 '^p- der'-mis). The plant is cov- 

 p^^ ered by a thin, translucent 

 skin tliat extends over the en- 

 tire surface of the leaves, stem 

 and root, called the epidermis 

 (Fig. 17 Ep.). This skin is 

 formed of comparatively 

 tliick-walled cells and serves 

 to protect the more delicate 

 parts within. It may be 

 Fi6. 17. Showing section through readily withdrawn in some 

 leaf of oidenburgh apple. .Ep. cp- p]ants, as froui the Icavcs of 



Idermis; Ftil. palisade cells; Jin- , • /. . 



terceiiuiar spaces. Highly magni- the livcforever * and echev- 

 fled. See also Figs. 1.3 and 20. gj-ja -j- and youug stcms of the 



l^lum. The exposed surface of the epidermis of the 

 leaves, fruit and youug stems of many plants is trans- 



*Sr'iliiiii telfjiliiuiii. i Co/ylerliin. 



