1915] 



ATKINSON PHYLOGENY IN THE ASCOMYCETES 359 



green leaved families and show very plainly the morpholog- 

 ical characters of their antecedents. But he says it is quite 

 otherwise with the fungi. The simplest primitive forms of 

 the Ascomycetes, Phycomycetes and Basidiomycetes have 

 given rise independently to an enormously high state of dif- 

 ferentiation. Now Sachs in 1896 (and earlier, 74, p. 310) 

 recognized Gymnoascus as belonging to the simplest Ascomy- 

 cetes, the sexual organs of which are a simple carpogone and 

 pollinode. It is very clear then that Sachs would not derive 

 the Ascomycetes from any primitive form at all like any 

 known red algae, much less through such forms as the highly 

 specialized Collema or Polystigma. This warrants us in con- 

 cluding that Sachs had in mind a primitive hypothetical an- 

 cestor of the sac fungi and red algae, which possessed simple 

 copulating gametes. With the knowledge we possess to-day 

 of such forms as Dipodascus, Eremascus, etc., where the 

 zygote becomes the ascus (generalized or simple) I believe he 

 would have recognized in the Phycomycetes, as we know them 

 to-day, a situation very closely approximating an ''Urform" 

 for the Ascomycetes, particularly in view of the fundamental 

 difference in the cytology of the red algae and sac fungi. 



But whether the fungi represent one or several architypes 

 it by no means follows that, because of the absence of chloro- 

 phyll, they must be derived from green plants, or that each 

 great series must be derived separately from different groups 

 of algae. 



The appearance of the higher fungi (Eumycetes) was, in 

 the opinion of Vuillemin ('12, p. 223), contemporaneous with 

 the emergence of sea-shore, which abandoned certain red algae 

 to a terrestrial life. This new environment introduced the 

 change, which, accompanied by loss of chlorophyll, gave rise 

 first to the Pyrenomycetes, from which the other higher fungi 

 {Uredinales, Basidiomycetes) have originated. The sapro- 

 phytic forms represent the productive and progressive stock. 

 Parasitic groups, like the Uredinales, Lahoulheniales, lichens, 

 etc., are composed of highly specialized and uniform members, 

 their progressive potentialities being suppressed, but they re- 

 tain their hold on existence because of their specialized hab- 



