LESSON 15.] 



CUTICLE. 



45 



268. This fact will be best illustrated by reference to the follow- 

 ing table : 



STOMATA IN ONE INCH SQUARE. 



Upper side. Under side. 



Mistletoe 200 200 



Tradescantia 2,000 2,000 



Rheum Palmatum 1,000 40,000 



Crinum amabile 20,000 20,000 



Aloe 25,000 20,000 



Clove-pink 38,500 38,500 



Yucca 40,000 40,000 



Mezereon None 4,000 



Poeony None 13,000 



Vine None 13,600 



Holly None 63,600 



Cherry-laurel None 90,000 



Lilac Few 160,000 



269. Stomata are not usually found on leaves always submerged ; 

 but in floating leaves they are restricted to the upper surface ; neither 



FIG. 79. 



FIG. 81. 



Cuticle, Ivy. 

 Cuticle, Euscus aculeatus. 



are they ever found on the upper surface of leaves which have a dense 

 shining cuticle. 



270. In Euscus aculeatus 

 (Butcher's broom, Fig. 79), 

 the cells of the cuticle are 

 very symmetrical, and the 

 stomata (a, a) well seen. 



271. The under cuticle of 

 the Ivy (Fig. 80), is distin- 

 guished by the* wavy lines, 

 which constitute the outer 

 walls of the cuticular cells; 



the stomata in this plant (a) Cuticle, White niy. 



are well marked, and of large size. 



272. In the White Lily (Fig. 81), the cells of the cuticle, and 



