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, 



u w V 



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 s 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 



