41 



poorer in cliloropliyll, and the cells are more 



elongated. 



The Rhizoids, i.e., Filaments whicL. attach the 

 plant to the substratum, and absorb water together 

 with the necessary food material, proceed from the 

 ventral surface, and are of two kinds. 



(1) Thin-walled ones, with peg-like projections in 

 the interior. 



(2) Thick- walled ones without peg-like projections. 

 Those with the peg-like projections in their inte- 

 rior lie close to the frond, and follow the midrib in 

 bundles and are covered by the scales. They serve 

 perhaps the purpose of stiffening the thallus. 



Those without the peg-like projections turn off 



from the thallus at once and enter the substratum. 



At their apex they are sinuately lobed, at their base 



purplish. 



The Scales are the leaves which are simple plates 



one cell in thickness. The median cells are living, 



but the outer edges become brown and die off. 



The projecting midrib consists of elongated thick- 

 ened cells which contain no chlorophyll. 



The Thallus grows by a group of apical cells. 



Throughout the entire tissue are single cells, which 

 are distinguished by a highly refractive, irregularly- 

 outlined, grape-like body, which in the youngest 

 shoots are slightly brownish, and in the older ones 

 dark brown. These are oil hodifis^ which are charac- 

 teristic of Liverworts. 



