WRIGHT: THE GENUS DIOSPTROS 
transverse sections only differ from the vessels in being 
usnally of smaller diameter. They are generally limited to 
the neighbourhood of large vessels, frequently flanking 
the tangential surface, but in D. Embryopteris they may 
occasionally be seen among fibres. 
The transverse dimensions are often only a trifle in excess 
of the largest wood parenchyma cells, but in some instances 
they attain a radial diameter of 0*04 to 0'08 mm. In length 
they come next to the fibres and may attain 0*27 to 090 mm. 
When of great length the ends taper very strongly, and in 
such cases it is difficult to distinguish them from the more 
abundant fibres, and the term “ fibre-tracheids ” would be 
very appropriate. The commonly small and constant trans¬ 
verse dimensions of true fibres seems to differentiate them 
from tracheids, but otherwise it often becomes well nigh 
impossible to distinguish a short fibrefrom a narrow lumined, 
long tracheid. 
•-cirencnymatous Elements. 
ra^lf 1 th IndeB th * W °° d Parench 5' ma > Mm* »nd medullary 
W m b“ e - tangential 
(2> ra y 3 are more than one cell 
m tangential breadth. 
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manner of variation^!!- t T ' na5 ' be 8 " bject *“ a11 
forces at work. ^ ° he internal and external 
the “e^rr h ^em^^°^ C0 “ P T‘ h ® greater P art of 
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