8 



ART. 



T. TCHTMUKA : OX THE FORMATION OF 



Microscopical structure. — It is noticeable that the epidermal 

 cells of the upper side become much projected upwards, assuming 

 the shape of a cap, whilst those of the lower side remain unchanged. 

 The glossy-white appearance of the calyx-leaf which is observed 

 at first is chiefly due to the abundant presence of air in the 

 intercellular space and partly also to the reflection of light by 

 the cap-shaped projection of the epidermal cells. Later, many 

 epidermal cells containing red anthocyan, besides those containing 

 the yellow variety, are found on the upper side, whilst on the 

 lower side coloured anthocyan has not yet made its appearance. 

 The microscopical study of the calyx-leaf of red Hortense 

 certainly reminds one of that of the flower-petals of several other 

 plants. 



The cnticnlar radiating striations of the upper side become, 

 finally, very distinct and the paralled striations of the lower side, 

 commonest in epidermal cells of all plants, also l)ecome visible. 



The air-spaces and the crystals of calcium oxalate show a 

 tendency to gradually decrease and are mostly concentrated toward 

 the hypodermal layers. 



The chemical reactions of red anthocvan are shown in Tal)le TL 



Table TL 



