432 



N. E. Stevens — New Jersey Palmoxylon. 



what larger than the parenchyma cells adjoining them and 

 their radial walls are for the most part regularly perpendicular 

 to the walls of the endodermal cells. Compare figs. 20, 21, 

 and 23. 



The vascular portions show the typical root arrangement, 

 the phloem strands alternating with the protoxylem groups. 



Fig. 16. 



Fig. 17. 



E 1 



Fig. 1G. Longitudinal section of inner region of cortex, showing endo- 

 derrnis (E), and a portion of the inner cortex with lignified parenchyma and 

 inner zone of three layers of cells (I), x 112. 



Fig. 17. Two of the large "stone" cells of the inner cortex in longitu- 

 dinal section, showing large pits, x 112. 



Fig. 18. 



Fig. 19. 



• %-r 



Figs. 18 and 19. Photornicographs of parenchyma cells of the inner 

 cortex in longitudinal section, showing nuclei (N) and cells which by their 

 shape seem to indicate recent division [y). Triangular intercellular spaces 

 may be seen in some cases, x 100 ± . 



In the larger roots there are usually fifty or more protoxylem 

 groups ; in the root from which fig. 20 was taken there were 

 fifty-five. The phloem groups and all the outer xylem ele- 

 ments are surrounded by a continuous zone of dense scleren- 

 chyma fibers. These sclerenchyma fibers are considerably 

 smaller near the vascular portions than they are toward the 

 center of the root. This dense sclerenchyma band is usually 



