CHERRY LAUREL. LEAF. 95 



1. Cuticularised layers, of granular appearance; 

 they are intermediate in properties between cuticle 

 and true cellulose. 



c. The cellulose layer, which abuts on the cavity 

 of the cell. 



i. These several layers may be readily distinguished in sections 

 treated with fuchsin. a and b stain much more deeply than c. 



ii. Treat sections with concentrated sulphuric acid, a retains 

 a sharp contour ; the rest of the wall swells, and loses distinct- 

 ness of outline. 



iii. Boil some sections for a long time with strong potash, a 

 and the cuticular granules of b will he dissolved, while c and 

 the cellulose matrix of b will remain. 



2. The Palisade parenchyma, composed of thin- 

 walled, oblong, closely-packed cells, with their longer 

 axes perpendicular to the surface of the leaf; the cells 

 are somewhat irregularly arranged in three layers; 

 observe nuclei and chlorophyll grains ; here and 

 there are cells with but little protoplasm (Idioblasts) 

 in which is inclosed a large crystal. Passing towards 

 the lower surface of the leaf, this tissue merges gradu- 

 ally into 



3. The Spongy parenchyma, the cells of which 

 resemble those of (2) in general characters ; but their 

 shape is various, and large intercellular spaces occur. 

 Idioblasts with crystals are scattered here and there. 

 Imbedded between (2) and (3) are 



4. Vascular bundles of various size ; the direction 

 in which these run is not uniform (cf. reticulate 

 venation of leaf) ; the positions of xylem and phloem 

 with regard to the whole leaf are the same as in the 

 Sunflower ; the bundles are surrounded by a continuous 



