On the Structure of the Axis of Lepidostrobus 
Brownii, Schpr. 
BY 
F. O. BOWER, D.Sc., F.R.S. 
Regius Professor of Botany in the University of Glasgoio. 
With Plates XVI and XVII. 
HOSE who examine sections of fossil plants microscopi- 
A cally are only too familiar with the gaps which occur 
in their tissues : these may have been due to the existence of 
lacunae in the living plant, or they may owe their origin to 
imperfect preservation after death of tissues present in the 
living state ; or both of these factors may combine to produce 
that discontinuity of tissues which is so frequently found in 
such specimens. It is only in the most perfectly preserved 
fossils that it is possible to decide how far the gaps present 
are due to the one or the other of these causes, while develope- 
mental evidence, which in the anatomy of modern plants 
would be at once called in to solve such questions, is usually 
unattainable in fossils. 
In some cases there can be little question that the lacunae 
were present in the living plants : this conclusion may be 
based upon examination of the tissues and comparison of 
[Annals of Botany, Vol. VII. No. XXVII, September, 1893.] 
