CELL-CONTENTS AND FORMS OF CELLS. 261 



the cell-contents. These thickenings assume a number of forms, 

 which are quite characteristic for the plants in which they are 

 found. They may have the form of transverse or oblique rings, 



FIG. 132. Phytomelane in root of Inula Helenium. 1-3 showing intercellular spaces 

 with carbon-like substance; 4-8, striated structure of intercellular phytomelane in sections 

 which have been allowed to remain in solutions of hydrated chloral or potassium hydrate 

 for some days; 9, a large crystal-like aggregate in a schizogenous-like reservoir formed in 

 contiguous intercellular spaces of 5 parenchyma cells; 10, separated crystal-aggregates 

 and rod-shaped masses of Phytomelane. After Senft. 



longitudinal spirals, or may be ladder-like or reticulate in appear- 

 ance (Figs. 141-144). In other instances the thickening of the 

 wall is quite complex, as in the wood of the pines and other Conif- 

 erse (Fig. 68). The thickening, or sculpturing, as it is sometimes 



