MICROSCOPIC STRUCTURE OF PHANEROGAMIC PLANTS 



377 



cut and polished by a lapidary's wheel. Should the Mfcroscopist be fortu- 

 nate enough to meet with a portion of a calcified stem in which the 

 organic structure is preserved, he should proceed with it after the manner 

 of other hard substances which need to be reduced by grinding ( 182-194). 

 377. Epidermis and Leaves. On all the softer parts of the higher 

 plants, save such as grow under water, we find a surface layer, differing 

 in its texture from the parenchyma beneath, and constituting a distinct 

 membrane, known as the Epidermis. 1 This membrane is composed of 



rf M^t ' VI^FH-' v 



ftitiiiS 



Epiderm of Leaf of Yucca. Epiderm of Leaf of Indian Corn (Zea Mais). 



cells, the walls of which are flattened above and below, whilst they adhere 

 closely to each other laterally, so as to form a continuous stratum (Figs. 

 272, 274, a, a). Their shape is different in almost every tribe of plants; 

 thus in the epiderm of the Yucca (Fig. 268), Indian Corn (Fig. 269), 

 Iris (Fig. 273), and most other Monocotyledons, the cells are elongated,, 



Portion of Epiderm of inferior surface of Leaf of Apple, with layer of Parenchyma in imme- 

 diate contact with it: a, a, elongated cells overlying the veins of the leaf; 6, 6, ordinary epiderm 

 cells, overlying the parenchyma; c,c, stomata; d,d, green eel 



open network near the lower surface of the leaf. 



green cells of the parenchyma, forming a very 



1 This term, borrowed from Animal structure, is singularly inappropriate in 

 Botany, since it properly designates a layer lying upon the derm or true skin: and 

 the Writer would have therefore preferred to retain the old term ' Cuticle,' were it 

 not that this is now applied by the highest authorities to the thin pellicle covering 

 the Epiderm ( 381). 



