SPOROBOLOMYCES 199 



do not develop a spore-hilum on one side of the top of the sterigma, 

 do not excrete a drop, and are not violently discharged. It is 

 probable, however, that the Gastromycetes and the Ustilaginaceae 

 have been derived from the same primitive Basidiomycete as the 

 Hymenomycetes, the Uredineae, and the Tilletiaceae. We may 

 suppose that the loss of the power of discharging the basidiospore 

 and the change in the morphological characteristics of the primitive 

 sterigma and basidiospore took place : (1) in the Gastromycetes 

 when the hymenium began to set free its basidiospores in closed 

 chambers instead of into the external air, and (2) in the Ustila- 

 ginaceae when the process of budding as a means of vegetative 

 multiplication was initiated. 



We may now ask the question : apart from Sporobolomyces, are 

 there any fungi other than undoubted Basidiomycetes which develop 

 and discharge their conidia in the same way as the Hymenomycetes, 

 the Uredineae, and Tilletia develop and discharge their basidio- 

 spores ? The answer to this question is that, up to the present, 

 no such fungi have ever been found either by myself or by anybody 

 else. In the literature of mycology there are numerous published 

 illustrations of the conidia of Phycomycetes, Ascomycetes, and 

 Fungi Imperfecti. I have examined a considerable number of them, 

 but I have not been able to find in any of them conidia shaped like 

 the basidiospores of the Hymenomycetes and Uredineae and having 

 a little spore-hilum projecting out on one side of the top of a 

 sterigma. I have, therefore, no reason to suppose that any of the 

 conidia under discussion are discharged by the drop-excretion 

 mechanism. 



The general conclusion to which my study of the production and 

 liberation of fungus spores has led me is as follows : the drop- 

 excretion mechanism of spore-discharge is characteristic of the 

 Basidiomycetes and is lacking in the Phycomycetes, the Ascomycetes 

 and, in general, in the Fungi Imperfecti. 



Since the drop-excretion mechanism of spore-discharge found in 

 Sporobolomyces is characteristic of Basidiomycetes and is not known 

 to occur in any Phycomycetes or Ascomycetes, we have strong 

 grounds for including Sporobolomyces in the Basidiomycetes. 



It is possible that Sporobolomyces is a degenerate genus of 



