dying, while Griffioen (13) contends that although lig- 
nification is a vital process, it proceeds with the necrosis 
of the cell content and the death of the cell. In this con- 
nection, it is significant that, following the formation of 
a lignified secondary wall, the septate fiber-tracheids of 
Hypericum Androsaemum remain alive with a function- 
ally active protoplast for a considerable period of time. 
SUMMARY 
The formation of septa in the fiber-tracheids of FZy- 
pericum Androsaemum L.. is reported. The development 
of the fiber-tracheids is normal in that they undergo elon- 
gation and maturation of the secondary wall. However, 
the protoplast remains active and usually undergoes divi- 
sion at aright angle to the original division of the cam- 
bial initial. This division consists of true karyokinesis 
followed by cytokinesis. The septum is formed in the 
region of the cell plate and the daughter nuclei migrate to 
the central portion of the newly formed compartments. 
As far as can be determined, the formation of septa is not 
confined to any particular region, but may occur in any 
part of the secondary wood formed during a single grow- 
ing season. The evidence is clear that the definition of 
a septate fiber-tracheid suggested by the Committee on 
Nomenclature of the International Association of Wood 
Anatomists is in agreement with the observable ontogeny 
and later development of the fiber-tracheid. 
In conclusion, the authors wish to thank Professor 
R.H. Wetmore, under whose direction the original work 
was started, and Professor I. W. Bailey, for their helpful 
suggestions and active interest in this work. 
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