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Lang . — Studies in the Morphology and 
of the xylem-gap scattered tracheides are present throughout the pith of 
the axis (Text-fig. io, d,e,f>g'> Phot. 31). Their distribution is shown 
diagrammatically in the reconstruction (Text-fig. 11). Still higher, on 
approaching the injured end of the axis, the xylem ceases to be lignified. 
The development of the tracheides throughout the pith of this stele is 
Text-fig. io. Series of transverse sections of the first branching specimen. Description in text. 
a matter of some interest. Comparison with uninjured plants shows that 
normally no tracheides would have been developed in this position. Their 
development may be related to the influence on the young main axis of the 
wounding or of the development of the branch ; probably the former is the 
important factor. Reasons have been given earlier in the paper for recog- 
nizing a poorly developed central or centripetal xylem in normal stems of 
Botrychium Lunaria . The scattered tracheides mixed with parenchyma in 
the pith of this wounded stele are most naturally regarded as a fuller 
development of this centripetal primary xylem. A point of interest is that 
