196 PRACTICAL BOTANY. 



N.B. The sieve-tubes are better seen in similar 

 sections of the Rhizome of Pteris. 



b. Cells of the conjunctive parenchyma inter- 

 spersed among the sieve-tubes. 



X. Separate some pieces of the vascular bundles from 

 the surrounding tissue, and warm them gently in a 

 test tube with potassium chlorate and nitric acid, till the 

 elements of the bundle may be separated easily one from 

 another ; then stop the action by diluting with water, and 

 mount in water. By preparing them in this way the 

 tracheides, (fee., may be subjected to separate examina- 

 tion, and their form and structure may be made out. 



Apply the same process to the sclerenchyma, and 

 observe the form and marking of the walls of its 

 constituent elements. 



XI. From around the apical bud of a well-grown 

 plant of the Male Fern remove successively the bases 

 of the leaves of previous years, those of the current 

 year, and finally the larger circinate leaves, which would 

 have unfolded in the following year. Carefully remove 

 the smaller ones with a scalpel, and then with forceps 

 gradually pull off the large mass of brown scales, which 

 completely cover the extreme apex. With a camel's- 

 hair brush remove the bases of these scales, together 

 with the youngest of them, which will still remain 

 round the punctum vegetationis; after this treatment 

 it will be easy to observe with a pocket lens 



1. The Apical cone (punctum vegetationis), a 

 rounded papilla, occupying a central and terminal 

 position in the flattened apical region. 



2. The young leaves, situated round the apical 

 cone, and successively larger the further they are from 



