Comparative A natomy of the Casuarineae. 2 5 1 
the first-formed vessels of a young stem of G. Gnemon % where 
a double row fuses to form a single row of perforations, as 
shown in Fig. 38, while most of the other vessels in the 
wood have a row of round perforations, some, however, 
showing one long, narrow perforation, marking thus a further 
higher modification in the fusion of several to form one 
perforation. 
Short-celled parenchyma occurs round the vessels in the 
wood of Gnetum . It is characterized by having thick walls. 
Sections of the wood of some were treated with iodine-solution, 
but no starch was seen, though there was abundance of it 
in the pith. 
The phloem of G. paniculatum , Benth., G, Thoa , R. Br., 
G. neglectum , Blume, and an unnamed Sumatran species, 
showed the following : — -sieve-tubes with oblique terminal 
walls ; compound sieve-plates on these and on the lateral 
walls. In some the sieve-plates on both walls were clearly 
seen without staining. The albuminous cells were very dis- 
tinct in some species ; they formed regular rows alternating 
with the rows of sieve-tubes, and occurred in the same radial 
line with the medullary rays in the wood. Though they 
sometimes look extremely like companion-cells, especially 
when, through the crushing of the elements, they come to lose 
their regular position and lie at the corners of the sieve-tubes, 
they are apparently formed from the same cambium-cell which 
cuts off the medullary ray-cells in the wood. Seen in longi- 
tudinal section, the albuminous cells are narrow, short cells, 
filled with dense, proteid contents. 
In the cortex are many greatly elongated brown fibres, and 
stone-cells similar to those seen in Casuarina and the Cupu- 
liferae. 
The protoxylem of Gnetum consists of elements with 
a dense spiral or reticulate thickening, amongst which bor- 
dered pits occur at intervals. In a few instances these pits 
appeared to be resolved into round perforations. 
In G. neglectum there occur, scattered through the wood, 
groups of much-elongated, thick-walled elements, with cell- 
