89 ELEME ^ 7 '. 1 /,' ) V/.s.s I 'KS. 



With an old razor or sharp knife, small sections of sufficient 

 thinness can be obtained from the surface of the nut. These may 

 be mounted in water for study, or in balsam for permanent preser- 

 vation. 



OBSERVE: 1. The tissue of the shell composed entirely of 

 sclerenchyma cells. 



2. The narrow cavities of the rectangular cells. 



3. Very thick but clear cell walls; cell contents. 



4. The tinbranched canals passing through the walls at var- 

 ious places. 



Enlargement of the canals at their place of union between con- 

 tiguous cells. In many cases tke septum between the two is not 

 absorbed. 



6. The peculiar branches of the canals at the end walls of 

 the cells. 



PREPARATION THIRD: SCLERENCHYMA CELLS from the underground 

 stem of Pterls aquilina, (common brake). Place some of the un- 

 derground stem between two pieces of cork, and fasten in the jaws 

 of a microtome. With a strong razor kept wet with alcohol cut 

 thin transections and mount in glycerin jelly for permanent preser- 

 vation. 



OBSERVE : 1. The bands of dark reddixh />/<>/'>! tixftue, ex- 

 tending across the section. These bands are composed of scleren- 

 chyma cells and assist greatly in strengthening the stem. (Fig. 23.) 



2. With the high power, the laminated thick inalls of the 

 cells. 



3. The branching canals through these walls. 



4. If the ends of canals of neighboring cells are in contact. 



5. By careful focusing, the- ends of these canals at the bottom 

 of some of the cells. 



Vines' Text Book of Bot., p. 133 ; Strasburger, p. 146 ; De- 

 Bary, 132 ; Goodale, p. 63 ; Sedgwick and Wilson, p. 76. 



IV and V Prosenchyma (in its widest sense.) 



IV. PROSENCHYMA (proper) or FIBROUS Tissue. 



(a) Bast-cells, in the bark, (derived from Pkhvm..} 



(b) Typical Wood-cells in the wood, (derived from 

 Xylerri). 



