426 COMPARATIVE MORPHOLOGY OF FUNGI 



nella type by suppression of the septa. The possibility of a development 

 of this sort can hardly be questioned if one admits that the phragmoba- 

 sidia have developed from conidiophores or otherwise ascribes to them a 

 great age; but if one considers that they are a recently developed form, the 

 conception of a further development of that type will meet with greater 

 difficulties. Perhaps in this connection serological investigations might 

 clarify the situation. 



While it is probable that the Basidiomycetes have developed from the 

 Ascomycetes, it is at present impossible to say exactly when, where and 

 how the different steps proceeded. The discussion of the question 

 whether the Basidiomycetes are a natural or an artificial group, is futile. 

 If one considers the transition from the endogenous to the exogenous 

 spore formation as a single occurrence, and consequently the different 

 types of basidia as having developed successively from each other, then 

 the class of Basidiomycetes is a natural one. If one is inclined, as the 

 author is, to the view that this transition was made in different parts of 

 the system of the Ascomycetes and that extensive possibilities for develop- 

 ment were realized within the Basidiomycetes themselves, then the Basi- 

 diomycetes are an artificial class and, with increasing knowledge, we may 

 determine the individual stocks more exactly. 



The present arrangement of Basidiomycetes is not considered final, 

 but states the problem. It rests, in contrast to that of the typical 

 Ascomycetes, not on the structure of the fructifications but on the struc- 

 ture and course of development of the basidia. The Basidiomycetes 

 are divided into Heterobasidiae and Autobasidiae. This arrangement 

 was originally conceived as horizontal in the sense that from the lower 

 stage with conidiophore-like basidia (Protobasidiomycetes) to the highest 

 stage of the more extensively modified Autobasidiomycetes, there arose 

 several parallel vertical lines of development. According to our concep- 

 tion, this arrangement should be understood in a vertical sense. The 

 Phragmobasidiomycetes and Autobasidiomycetes are connected by 

 common roots and have developed considerably parallel to each other. 

 If this conception should prove correct there should be substituted as 

 above mentioned for the expression proto- and autobasidiomycetes, the 

 more neutral expressions phragmo- and holobasidiomycetes. Whether 

 one will place the Holobasidiomycetes at the beginning and the Phrag- 

 mobasidiomycetes at the end as Patouillard (1900) and Rea (1922) 

 advocate, or whether one will leave them in the order previously used in 

 Germany, the future alone must show. Didactically, the placing of the 

 Autobasidiomycetes first is better and will be followed, since the tradi- 

 tional German arrangement has not become general among English- 

 speaking peoples. 



The Phragmobasidiomycetes are distinguished by gelatinous fructifi- 

 cations often comparatively poor in nutritive matter, by generally irregu- 



