158 PRACTICAL BOTANY 



exposed as above, and boil it in dilute hydrochloric acid till the 

 parenchyma is soft : for further treatment of this see below. 

 Meanwhile smooth the cut end of the remainder of the stock 

 with a razor, so that it may present an even surface of trans- 

 verse section, and observe 



<2. The great irregularity of outline, due to the close crowd- 

 ing of the bases of the leaves. 



b. The dark brown band of sclerenchyma bordering the 

 periphery of the section. 



c. The great bulk of the stem consisting of yellowish 

 parenchyma, with very bulky central pith, 



d. Round the latter are a number of isolated, large vascular 

 bundles, forming an interrupted ring. 



e. Outside these, and running out into the leaves, are 

 numerous smaller bundles of the leaf-trace, which appear to 

 be less regularly arranged. 



IV. Divide the stock, including the apical bud, into two 

 symmetrical halves by cutting it in a median longitudinal 

 plane : smooth one of the cut surfaces with a razor, and 

 observe 



a. That the stem is of almost equal thickness throughout its 

 length, i.e. it is roughly cylindrical. 



b. That its external conformation is very irregular by reason 

 of the closely crowded insertion of the leaves. 



c. The bulky central pith as before. 



d. The large vascular bundles (d above), which are not con- 

 tinuous in direct longitudinal lines, but form an interrupted 

 series. 



e. The smaller bundles of the leaf-trace (e above), which 

 in some cases may be followed, after a little careful dissection 

 of the parenchyma which surrounds them, from one of the 

 larger bundles of the central system into the base of one of the 

 leaves. 



Slice away carefully the external tissues of the posterior part 

 of the stock, so as to lay bare the central system of larger 

 bundles : it will then be seen that these form a continuous 

 network with large meshes, and that each mesh is opposite the 

 point of insertion of one of the leaves, hence it is called a 



