10 PKACTICAL BOTANY. 



glycerine or glycerine jelly. Being a cylindrical organ 

 the transverse section is circular. Note 



1. The superficial layer of cells with a definite cuticle 

 and thick yellow walls. 



2. A band of brown sclerenchyma, which graduates 

 internally into 



3. A thin-walled parenchyma with large inter- 

 cellular spaces, and containing chlorophyll. 



4. Centrally is a strand of denser tissue without 

 intercellular spaces. 



XI. Cut median longitudinal sections of the base of 

 the seta, which is inserted on the apex of the Moss-plant 

 or oophore : mount as before, and note in the upper 

 part of the seta the superficial layer, brown scleren- 

 chyma, thin-walled parenchyma, and central strand, as 

 above described. Following the seta down to the base, 

 it will be seen that the cuticle and brown sclerenchyma 

 stop short, and are replaced by thin-walled parenchyma 

 with plentiful protoplasm ; this tissue of the sporophore 

 is in close connexion with the inner surface of the 

 vaginula, which belongs to the oophore generation. 

 With this close physiological connexion of the sporo- 

 phore and oophore in the Moss, compare the connexion 

 by means of the foot in Ferns. 



Similar sections may be prepared, with similar results, from 

 plants of Funaria, but there will be greater difficulty in this case, 

 owing to the smaller size of this Moss. 



XII. Passing now to the apex of the sporogonium 

 of Polytrichum remove the calyptra : mount it in 

 water or weak glycerine, and examine under a low 

 power. It consists of dry, often branched, hypha-like 

 filaments, loosely matted together : the neck of the 



