456 



BOTANICAL GAZETTE 



[DECEMBER 



sections show that they are typical, vertically elongated wood 

 parenchyma. The rays of Gnetum are multiseriate or broad. 



The appearance of this parenchyma in the mature wood is 

 shown in fig. 5. At the end of the season's growth, where the 

 fibers are small and vessels lacking, the wood parenchyma forms 

 continuous rows (lower part of figure), but with the increase in 

 size of the fibers and the introduction of vessels at the beginning 

 of the next season's growth, the parenchymatous cells become 





iSSSnX 



Fig. 4 



Fig. s 



Figs. 4-5. — Fig. 4, wood, cambium, and young bast of Gnetum latifolium show- 

 ing sieve tubes and companion cells formed from different rows of cambial cells; 

 also wood parenchyma formed inwardly from those cambial cells which form com- 

 panion cells; Xiooo; fig. 5, wood of Gnetum latifolium showing radial rows of wood 

 parenchyma; Xiooo. 



separated just as do the companion cells of the bast. Often where 

 the vessels are large the rows of elements of all sorts become so 

 distorted that they can no longer be traced. The elements then 

 appear to be haphazardly arranged. 



In certain regions of some species of Gnetum particularly inter- 

 esting and primitive conditions of the companion cells are found. 

 In the root of G. scandens, for example, the companion cells do 

 not become separated and relegated to the corners of the sieve 

 tubes, but form continuous rows, even in old bast. This condi- 



