532 RESEARCHES ON FUNGI 



basidium probably soon became curved with the sterigmata and 

 spores produced on the convex side of the filament, for this would 

 favour the dissemination of the spores. We may suppose that 

 the most primitive Basidiomycetes were saprophytes. Some of 

 these fungi with curved basidia may have become parasitic, have 

 then developed resting probasidia or teleutospores, and thus have 

 become the Uredineae, whilst the others remained as saprophytes. 

 Even at the present day there are certain hymenomycetous sapro- 

 phytes with curved basidia, e.g. Helicobasidium. We may suppose 

 that during the further evolution of these saprophytes the basidia 

 became associated together to form a hymenium. With the develop- 

 ment of a definite hymenium in which the basidia gave each other 

 mutual support, the originally curved basidia may have become 

 straightened with the retention of the transverse septation and 

 the lateral production of sterigmata. This condition we find in 

 the Auricularieae at the present day. The straightening of the 

 basidium, however, may have taken place more than once — in the 

 Auricularieae with the production of a gelatinous matrix and in 

 the non-gelatinous Hymenomycetes without the production of such 

 a matrix. The absence of a gelatinous matrix in the latter fungi, 

 by bringing the basidia closer to one another, may have favoured 

 the evolution of the hymenium from a somewhat loose to a perfectly 

 compact form. As the compact hymenium underwent evolution 

 in the non-gelatinous Hymenomycetes, the basidia probably lost 

 their septa and changed from the cylindrical to the clavate form, 

 while the sterigmata moved upwards to the top of the basidia, 

 became reduced in size, and came to develop their spores so that 

 the hila were all turned toward the basidium-axis. 



Whilst making the investigations on the basidia of Puccinia 

 graminis and Endophyllum Euj)horbiae-sylvaticae which have already 

 been described, I concentrated my attention chiefly on the phenomena 

 connected with the discharge of the spores from the sterigmata, 

 such as the excretion of the water-drop and the distance of 

 spore-discharge, and it was only subsequently that I realised 

 the importance of the curvature of the basidium. The drawings 

 of the basidia of these fungi were therefore not made with any 

 effort to lay stress on the curvature ; moreover, for the Puccinia, 



