BASIDIOMYCETES 427 



lar hymenia (protohymenial type) and by the germination of their spores 

 with imperfect forms. Some of these characteristics, e.g., the gelatiniza- 

 tion of the fructifications (water adsorption!) and the germination of the 

 basidiospore, may be influenced much by environment, but these condi- 

 tions in the same environment have affected the Phragmobasidiomycetes 

 more strongly than the Holobasidiomycetes. The further subdivision of 

 the Phragmobasidiomycetes rests upon the arrangement of the septa; 

 the Auriculariales, Uredinales and Ustilaginales possess Auricularia 

 basidia, the Tremellales cruciate basidia. 



The Holobasidiomycetes are distinguished by decreased conidial 

 formation, by increased oidial formation and by fibrous fructifications, 

 often filled with nutrients, by regular hymenia (Euhymenial type) and 

 by the germination of the basidiospores by germ tubes. Some of these 

 characters may be determined by other influences, e.g., the decrease of 

 conidial formation by the suppression of the haplont, and the direct 

 germination of the basidiospores by the thickening of the spore walls, 

 which is unfavorable to the formation of sprout cells (cf. in the Phragmo- 

 basidiomycetes, Phleogena with thick-walled basidiospores, germinates 

 directly with a germ tube). 



The further arrangement of the Autobasidiomycetes is still an un- 

 solved problem. Formerly a few characteristic orders, the Dacryomyce- 

 tales, the Plectobasidiales and the Gasteromycetes were distinguished and 

 the rest were left in the Hymenomycetes, as if the majority of the Basi- 

 diomycetes did not possess hymenia. In order to meet this difficulty, we 

 will attempt to segregate the orders on the basis of stichobasidium and 

 chiastobasidium. It is true, indeed, that the phylogenetic significance 

 of both these types still remains an open question, that this system 

 becomes rather incomplete by the use of cytological characters (on 

 account of the small number of investigated forms) and that a separation 

 of the converging forms, conducted on cytological foundations is tiresome 

 for the systematist of the herbarium. On the contrary the contrast of 

 stichobasidium and chiastobasidium within the fluctuating forms of the 

 Autobasidiomycetes which are connected by numeroust ransitional forms, 

 is the only constant recognizable pair of characters at present, and, 

 consequently, is more reliable than the structure of the hymenium and of 

 the fructification. It is not the problem of a work of this kind to make 

 easy the recognition and identification of an unknown fungus, but to 

 discuss fundamental questions of relationships and to point out gaps in 

 our knowledge. 



The stichobasidial group is still poorly known. It is divided accord- 

 ing to the structure of its basidia into two orders, the Dacryomycetales 

 and the Cantharellales. 



The chiastobasidial group contains a large majority of the Autobasi- 

 diomycetes. They are divided into three forms on the basis of their devel- 



