LYCOPODIUM. SPOROPHORE. 181 



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 communication between the cavities of these 

 elements, and they have no cell- contents remaining; 

 they are therefore scalariform tracheides (compare 

 those in the xylem of the Fern, and the tracheides of 

 Pinus.) 



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 Pinus : 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 a longitudinal direction ; 

 they have transparent contents, and their cellulose 

 walls are dotted with minute pits, about which bright 

 globules adhere. These are probably the representa- 

 tives of the Sieve-tubes of the Phanerogams. 



Stems of other species of Lycopodium 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 

 same as that described for Lycopodium clavatum, the differ- 

 ences depending chiefly upon the number of plates of xylem and 

 phloem, and variations in the manner and extent of the connec- 

 tion between the plates of xylem. 



