238 CALTFORNTA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



as well in a liquid medium as upon a solid one, but they 

 will not aggregate into the same form. So the fungus 

 component of a lichen, grown by Moller on liquid media 

 and alone will not form a body like a lichen in structure, 

 growth, habit, color, etc., although it will develop perfectly 

 well. Both substratum and associate will affect the fungus, 

 and the lichen is the product, the resiiltafit, of all these injlu- 

 etices, not of one or two. 



VIII. The varying mechanical pull exerted by itself and 

 by the wind upon R. 7'eticulata influences its growth in the 

 three dimensions of length, breadth and thickness. 



IX. The central body of the gonidial cells of Ramalina^ 

 Usnea, and Sphcerophorus, which are Cystococcus huinicola 

 Nag., is a nucleus, not a pyrenoid. 



Stanford University, 

 California, 



December, 1898. 



