LYCOPODIUM SPOROPHYTE 281 



of Finns (p. 240), from which these elongated pits differ 

 only in their outline as seen in surface view. Some of 

 the walls will have been cut through longitudinally : 

 examine a section of one of them, and note especially 

 that the pit-membrane is constantly present ; there is 

 thus no direct communication between the cavities of 

 these elements, and they have no cell-contents remain- 

 ing ; they are therefore scalariform tracheides : 

 compare those in the xylem of the Fern, and the 

 tracheides of Finns (p. 238). 



iii. Where the sections have passed through the 

 peripheral margins of the plates of xylem, there will be 

 found elements of the protoxylem, which correspond 

 in structure to those in the stem of Films : irregular 

 finger-like outgrowths of the cell-wall may be observed 

 extending into the cavity of these elements. 



iv. The phloem, intervening between the masses of 

 xylem consists of 



a. Prosenchymatous cells with cellulose walls, and 

 granular cell-contents : these are directly in contact 

 with the xylem. 



b. Long tubular structures, the pointed endings of 

 which are very rarely met with : their course may be 

 followed for a considerable distance in the longitudinal 

 direction : they have transparent contents, and their 

 cellulose walls are dotted with minute pits, about which 

 bright globules adhere. These are probably the re- 

 presentatives of the sieve-tubes of other vascular 

 plants. 



Stems of other species of Lycopodiam may be treated in the 

 same way, and a comparison made of their structure : the general 

 arrangement of tissues will be found to be fundamentally the 



