A VEX A SATir.l. 183 



e. Trace them backward ; notice that the plerome 

 becomes the fibro-vascular bundle ; the periblem, 

 the cortical parenchyma ; the dermatogen, the 

 epidermis. 



Cut a transverse section of the oldest part of a root which 

 has grown on blotting paper. Examine with a high power. 

 Compare with the section of the large lateral roots, already 

 studied. Notice 



1 8. The origin of the root-hairs. 



19. The differences in the fibro-vascular bundle, particularly 

 the presence of a large axial vessel. 



r>. THE STEM. Cut a transverse section from one of the 

 younger parts of the stem, e. -., between the flower cluster 

 and the first leaf. Examine with a low power, and note 



1. An outer cortical part, of varying thickness, composed 

 of small dense-looking cells, the epidermis and hypo- 

 derma. 



2. In the cortex lighter spots, in pairs, at almost regular 

 i ntervals, chloropJn 'll-bcaring parenchyma. 



3. An inner part, consisting of large empty parenchyma 

 cells, the fundamental parenchyma, with fibro-vascular 

 bundles at regular intervals. 



Examine with a high power. Study 



4. The epidermis. Note the thick walls, showing two 

 layers, and the cuticle. Draw. 



a. Observe in some sections a pair of smaller, peculiar 

 cells in the epidermis over an intercellular space 

 in the chlorophyll-bearing parenchyma, the guard 

 cells of a stoma. The two adjacent epidermal cells 

 are also modified somewhat. Draw. 



5. The hypoderma. Note the thick walls of the cells 



