ccxviii GENERAL SUMMARY OF SCIENTIFIC AND 



in the air, very rarely submerged, and are parasitic ; lichens 

 are composite plants, having fruit similar to fungi and thalli, 

 which are composed of hyphae, or threads, in which are vari- 

 ous-shaped alga-like bodies called gonidia. Sachs does away 

 with these three divisions, and divides all the Thalloirens into 

 two parallel groups one in which the members contain chlo- 

 rophyl, the other in which they are destitute of it. There 

 has long been observed a parallelism between certain groups 

 of fungi and algae, as between the Conjugate of the algae and 

 the Mucorini of the fungi. Sachs brings such parallel groups 

 together, and divides each group into two portions, in one of 

 which the plants contain chlorophyl, in the other of which 

 they do not. Sachs's scheme is as follows: 



THALLOGENS. 



First Class. 



PROTOPHYTES. 



Containing Chlorophyl. Without Chlorophyl. 



Cyanophyceaa. Schizomycetes. 



Palmelleie (in part). Saccharomyces. 



Second Class. 



ZYGOSPORE. 



Containing Chlorophyl. Without Chlorophyl. 



Conjugation of Moving Cells. 

 Volvocineae. Myxomycetes. 



(Hy drodictyeae. ) 



Conjugation of Stationary Cells. 

 Conjugatece (incl. Diatomes). Zygomycetes. 



Third Class. 

 OOSPORE. 

 Containing Chlorophyl. Without Chlorophyl. 



Sphaeroplea. Saprolegniacece. 



Vaucheria. Peronosporeae. 



CEdogonieae. 

 Fucaceae. 



Fourth Class. 



CAEPOSPOEiE. 



Containing Chlorophyl. Without Chlorophyl. 

 Coleochceteae. Ascomycetes. 



Florideae. iEcidiomycetes. 



Characea). Basidiomycetes. 



Sachs regards the presence or absence of chlorophyl as a 

 physiological, not a structural character, and consequently 





