2o8 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 30 Ser. 



Other than superficial characters would repay the investi- 

 gator. To the physiologist they especially appeal because 

 they are not simple organisms, but an association of two 

 simple organisms. 



The nature of the association is variously regarded, from 

 pure parasitism of one member upon the other, to associa- 

 tion mutually beneficial, if not absolutely necessary, to the 

 two. Schwendener has always regarded the association as 

 pure parasitism of the fungus upon the alga, and his school 

 advocates the same view. The opposite view is held by 

 Reinke (1894) and his sympathizers, of whom Schneider 

 (1896a) is at the moment perhaps the most conspicuous in 

 this country. Reinke believes that the association is what 

 he names Consortism, and that the " Consortium " is as 

 " autonomous" as any plant. 



A question to which there are such opposite answers by 

 such eminent investigators cannot be regarded as answered 

 at all. This paper is a contribution to the discussion, and I 

 shall be glad if the account of my work and its results leads 

 at all to the solution of the problem. I must remark at the 

 outset that much of my work may not be new ; how much 

 I cannot say, for though I have tried, I have not been able 

 to have access to all the literature on this subject. Further- 

 more, no one should venture, from the study of only a 

 few forms, to draw conclusions regarding a great number, 

 although the careful examination of a few forms will just- 

 ify opinions regarding the others, if only these opinions 

 are held tentatively, subject to modification by further 

 researches. 



Beginning with Ramalina reticulata Krplhbr., a lichen so 

 large that it forms a conspicuous feature of the landscape 

 in some parts of California, I have examined several 

 species and genera of lichens occurring hereabouts, and 

 not trusting merely to microtome sections of " fixed " 

 material, I have had recourse to experiments and cultures 

 on and of living material. The difficulty of minutely 

 studying lichens alive is notoriously great, not least because 

 of their extremely slow growth. Yet in their rates of 



