26 WOODY TISSUE. 



vessels with the fibre broken into short pieces, and attached 

 to the tube and is called Continuous Bothrenchymaf differing 

 from the one above described in having no interruptions 

 caused by the adherence of the cells. 



Section 3. — Woody Tissue, 



25. The woody tissue consists of elongated vessicles tapering 

 at each end to a very fine point, (fig. 10.) It is customary to 



^O consider this tissue as a distinct variety, yet, although 

 it is convenient to consider it by itself, we believe it is 

 only another form of the cellular tissue. Several ob- 

 jections are urged by different botanists against its be- 

 ing considered a form of this tissue. First, its tough- 

 ness, but this property it acquires by deposition of for- 

 eign matter, and by the number of fibres found associa- 

 ted together. Second, its length ; but this is not a val- 

 id objection, since we know no reason why a cell may 

 not be developed indefinitely in any direction. Third, 

 its tapering extremity ; but we find cells not unfrequent- 

 ly attached to each other by a slanting, pointed termination. 

 Our reasons for believing it a modification of the common cel- 

 lular tissue are, First, in many instances they run impercept- 

 ibly into each other, and in their young state cannot be dis- 

 tinguished. Their constitution, and arrangement of the parts 

 in their early stage, are also the same. The tubular form of the 

 fibre having a pointed termination at both ends, is admitted 

 by all, and this is the form a cell would necessarily take if 

 developed only in length. 



26. It is the fine shining fibres, which are readily distin- 

 guished in wood, and which are composed of many woody 

 fibres, formed into bundles. So minute are the individual 



fibres, that the finest filament of flax, which is 

 composed of woody fibre, is made up of a great 

 number of these fibres joined together ; their fine 

 tapering extremities being spliced to like fibres, 

 as seen in fig. 10, which go to make up the long 

 fibre extending through the whole plant. Cotton 

 is of the common cellular formation. A modifi- 

 cation of the woody fibre occurs in the conifer- 

 ous plants ; the individual fibres are larger in this 

 family, and are marked by glandular dots regu- 

 larly arranged as seen in fig. 11, and these may be easily 

 seen in the thin longitudinal slice of the pine placed in water 

 and viewed through a microscope. 



