A NOTE ON THE WOOD OF GNETUM GNEMON 
83 
are present in the vessels of Ephedra are not found here. Striations, 
however, are present in some vessels. One large perforation is exceedingly 
common, although as many as 10 occur, and fusions of the perforations are 
seen. Transitions between bordered pits and perforations were not found 
in this material, but it seems evident that the perforations in the vessels 
have been derived from the bordered pits of tracheids. As in Ephedra 
altissima vessels are present in the node. 
Wood parenchyma. The wood parenchyma is not so abundant as the 
tracheids. It is scattered irregularly amongst the tracheids, and often almost 
or entirely surrounds the vessels. The cells are lignified, uninucleate, have 
simple pits, and contain starch. Transverse septa are abundant and usually 
stain easily in Delafield’s Haematoxylon. In some cases the septa show one 
or two lignified lumps in the middle, occasionally being entirely lignified ; in 
a few cases simple pits occur. 
In Ephedra 1 the parenchyma cells are often multinucleate and are 
identical in length and shape with the tracheids. They are described as 
being merely tracheids, except for their pitting, which have retained their 
protoplasmic contents. In a few cases only in Ephedra do the parenchyma 
cells show septa,- these being typically oblique. In G. gnemon a row of 4 to 
8 of these cells resembles a tracheid in size and shape, so that in this case 
septation of the tracheid to form parenchyma has gone much further than in 
Ephedra and resembles the coniferous type. 
Wood Rays. The width of the rays in transverse section is from 1 to 8 
cells, 3, 4 and 5 being most common. In radial section they vary in height 
from 4 to 60 or 70 cells, and in tangential section show a fusiform shape. 
The individual cells of the ray vary much in size and shape. Some are 
elongated radially, others vertically, while some are almost square in section, 
Each cell is lignified, uninucleate, simply pitted, and contains starch and 
calcium oxalate crystals. 
In young stems uniseriate rays start from the pith, and in their course 
towards the periphery of the wood the cells divide radially (fig. 4), giving 
first biseriate then multiseriate rays. There is evidence of the fusion of 
smaller rays to form compound rays, although complete fusion has not been 
seen in this material, probably because it is not old enough. These smaller 
rays, when fusing, enclose part of the wood which often contains several 
vessels, and when they have reached the periphery there is usually only one 
row of wood elements separating them, so that in older material complete 
fusion might reasonably be expected. 
Tangential sections show that many of the rays are intersected by xylem 
parenchyma (fig. 6), and in old stems uniseriate rays are found which do not 
arise from the pith, but amongst the elements of the wood. 
1 Thompson, 1912. 
