The saprophytic nutrition referred to here took place, not only on one nutrient substratum, 

 but on any which were used for the culture. The parasites accordingly behaved outside of the 

 host plant just as do other fungi which live saprophytically and do not exist simultaneously as 

 parasites. 



In cultures in clear nutrient substrata, it was shown further that the conidia formed by 

 the germination of the spores were increased in many places by direct budding without change 

 of form. They illustrate in this manner of reproduction different forms of budding fungi 

 which are characterized by the form of the bud, by the definite place of budding and the early 

 separation of the budded members from one another. These bud conidia, which were increased 

 through unceasing budding until the nutrient substrata were exhausted, are therefore proved here 

 to be released developmental members of our smut fungi, however much they outwardly give 

 the impression of ordinary yeast fungi. Some of these bud conidia are able to continue their 

 budding in the air also and to form conidia there which are disseminated through the air; as, 

 for example, the bud conidia of the maize smut. The germinating spores of the different forms 

 of smut fungi in nutrient solutions are illustrated in Part V of this work^ and especially the bud 

 conidia, which, belonging there, were then pictured as they are produced at the period of exhaus- 

 tion of the nutrient substrata. 



In Part XII of this work may be found further statements on the germination of smut 

 spores, especially on the morphologic decision as to spore germination in promycelia with sporidia. 

 In order to interpret this correctly, extensive investigations on Basidiomycetes, continued for 

 many years, had to take place first; — the results of which are united in Parts VII and VIII of 

 this work- It was shown that the basidia of the Basidiomycetes occur in two different forms ; 

 once as definitely organized basidia, each forming one spore from each cell, and then as unicel- 

 lular, unorganized Ijasidia which produce at the tip a definite number of spores, mostly four''. 

 These two forms of basidia, named Protobasidia and Autoljasidia, showed a striking correspond- 

 ence with the two forms of promycelia which were formed in the germination of the smut 

 spores. The formal production of the promycelia in the one type of Ustilagineae corresponds 

 perfectly with the form of the basidium of Protobasidiomycetes and, in the same way, the undi- 

 \ided promycelium in Tilletia with its apically formed sporidia is formed exactly like the basidia 

 of Autobasidiomycetes. The difference between the above named formal types of the smut fungi 

 for the one part, and the two basidia forms of the Basidiomycetes for the other part, consists 

 only in the fact that the number of spores in the former is still indefinite, but in the latter has 

 become definite*. The jjromycelia are therefore nothing but basidia which have not yet reached 

 the higher and typical formation of the basidia. The basidia of the Ustilagineae are accordingly 

 the first stages of the actual basidia in Basidiomycetes. They explain the natural course of mor- 

 phological differentiation which has held in the formation of the basidia. The organization and 



(1) Compare the illustrations on the 13 plates in Part V of this work 1. e. 



(2) Compare with these the illustrations on the plates in Parts VII and VIII of this work. 



(3) Compare with these the illustrations on the plates in Parts VII and VIII of this work. 



(4) The illustrations on the plates in Parts V and XII should be compared with those in Parts 

 VII and VIII as mentioned above. 



