4S2 ELEMENTARY BIOLOGY. [CHAP. 



/>. The roo/s springing from the rhizome. 



i. The haves or fronds arising from the rhizome at 

 intervals, along the lateral lines, 

 tt. The great amount of subdivision of the frond : 

 its main axis irachis); the primary divisions or 

 pinnce ; the ultimate divisions ox pinnules, 

 [i. The sort ; small brown patches along the 

 margin of the under surface of some of the 

 pinnules, 

 y. The indushini or membrane covering the 

 sorus. 



d. The nodes and internodes of the rhizome. The 

 naked growing point at its extremity. 



b. The rhizome. 



1. Cut it across and draw the section as seen with the 

 naked eye. 



a. The outer brownish layer (epidermis and /lypo- 

 derfna) ; the latter thins aways somewhat oppo- 

 site the lateral lines. 



b. The yellowish-white substance {ground-substance 

 01 parenchyma) forming most of the thickness of 

 the section. 



c. The internal incomplete brown ring {sclcrejicJiyma) 

 imbedded in the parenchyma. 



d. The small patches of sclerenchyma scattered 

 about in the parenchyma outside the main 

 sclerenchymatous ring. 



e. The yellowish tissue {7'ascu/ar bundles) lying in- 

 side and outside the ring of sclerenchyma. 



2. Cut a longitudinal section of the rhizome ; make out 

 on the cut surface b. i. ^, b, r, d^ e. 



