534 CLASS BASIDIOMYCETEAE 



The logical classification into orders, families, and genera of the 

 Gasteromycetes depends upon the probable course of evolution in the 

 group. The undeniable points of similarity between some of the Agari- 

 caceae and various unipileate Gasteromyceteae, e.g., Elasmomyces, Seco- 

 lium, Montagnea, etc., have already been mentioned. Heim (1934) in fact 

 includes Family Hydnangiaceae in the Agaricales, and others have placed 

 Secotium and Montagnea in the same order. The fact that the basidiospore 

 in all Gasteromyceteae is symmetrically perched at the tip of the sterigma 

 and is not shot off from it makes a derivation of the Agaricales from them 

 difficult, while the loss of these characters would not be so difficult to 

 imagine if some Agaricaceae became gasteromycetous in structure and 

 habit. It must be remembered that the genus Hyaloria in the Hetero- 

 basidiae has the basidia enclosed in a sort of loose peridium and the 

 basidiospores there are symmetrically placed and not shot away. Prac- 

 tically all of the other Heterobasidiae have the usual type of basidium. 

 The occurrence of transitional forms from Secotium and the apparent 

 close relationship to some other genera of Gasteromyceteae is an argument 

 in favor of the theory that there is a close connection between both 

 groups. Yet it is difficult to imagine simple forms like Protogaster and 

 Gasterella as being derived from the very complicated Secotiaceae. In view 

 of the fact that so much investigation still remains to be done on the 

 development of the spore fruit of many species and genera before a com- 

 pletely satisfactory conclusion can be arrived at as to the classification 

 and arrangement within the group the author has decided to follow 

 Eduard Fischer (1933) in the main, with modifications that seem to him 

 to be necessary because of more recent studies, especially on Protogaster, 

 Gasterella and Gasterellopsis, and some of the more secotioid genera, 

 Gyrophragmium, Battarrea, etc. 



The Gasteromyceteae may be arranged in several parallel series, each 

 ranging from simple to complex structures (or possibly the reverse). As 

 outlined below the groups with simple structures are placed first. In one 

 series the spore fruit is mainly fleshy, with well-developed hymenial 

 chambers. It does not undergo partial autodigestion and depends upon 

 decay or mechanical destruction for the distribution of its spores. This 

 series contains forms of increasing complexity from Protogastraceae to 

 Hymenogastraceae and on to Sclerodermataceae on the one hand and on 

 the other through the Hydnangiaceae and finally to the Secotiaceae, 

 which last family has close connection with the Agaricaceae. Another 

 series leads from the partially gelatinous or cartilaginous Ilysterangiaceae 

 to the Clathraceae and Phallaceae, with increasing tendency to the auto- 

 digestion of the gleba to form a slimy, evil-odored mass attractive to 

 insects which distribute its spores. A third series, arising again in the 

 Hymenogastraceae leads to the Lycoperdaceae and Geastraceae, and 



