GENERAL SUMMARY 379 



The development and violent discharge of the so-called secondary 

 conidia of Tilletia tritici are described in detail. A secondary conidium 

 takes 1 • 25-1 • 50 hours to develop from a tiny rudiment to maturity. As 

 soon as it is mature, it is shot away from its sterigma along with a drop 

 of liquid excreted at its hilum. The development and discharge of the 

 secondary conidia of Tilletia laevis take place in exactly the same manner 

 as in T. tritici. 



The authors' theoretical conclusions in regard to the nature of the 

 basidium of Tilletia tritici, which differ from those of Brefeld, are stated 

 in the next two paragraphs. 



The sickle-shaped so-called secondary conidia of Brefeld and others 

 are the true basidiospores of Tilletia tritici. 



The long slender so-called primary conidia of Tilletia tritici of Brefeld 

 and others are sterigmata of a highly specialised type. 



Conjugation in Tilletia tritici takes place at an earlier stage than in 

 the heterothallic Hymenomycetes, for the conjugating elements are two 

 haploid sterigmata instead of two haploid mycelia developed from 

 basidiospores. 



The primary basidiospores of the authors correspond to those sickle- 

 shaped secondary conidia of Brefeld which are produced on the H -shaped 

 pairs of his primary conidia ; and the secondary basidiospores of the authors 

 correspond to those sickle-shaped secondary conidia of Brefeld which are 

 produced on a mycelium. A comparison of the authors' newly proposed 

 terminology and of the terminology of Brefeld, as applied to the basidium 

 of Tilletia tritici and its products, has been set out in a Table. 



The nuclear condition and sexual processes of Tilletia tritici have 

 been discussed. The primary basidiospores contain two haploid nuclei 

 and the secondary basidiospores one haploid nucleus. The fungus may 

 be regarded as homothallic in one stage of its life-history and heterothallic 

 in another stage. 



The asymmetrical development of the basidiospores of Tilletia tritici 

 and their violent discharge with drop-excretion is in exact conformity 

 with what is found in the Hymenomycetes and the Uredineae. This fact 

 strongly supports the view, held by most botanists, that the Tilletiaceae 

 belong to the great group of the Basidiomycetes. 



The abnormalities in the discharge of the basidiospores of Tilletia 

 tritici, particularly in respect to excessive drop-excretion, are similar to 

 those which have been observed by other workers in the Hymenomycetes, 

 the Uredineae, and the Sporobolomycetes. 



The authors' view that in Tilletia tritici the secondary conidia of 

 Brefeld are in reality the true basidiospores is supported not only by the 

 mode of development, asymmetrical shape, and mode of discharge of the 

 secondary conidia, but also by a comparison of the basidial apparatus of 

 T. tritici with that of other Tilletiaceae, namely, Urocystis violae, Tuber- 

 cinia trientalis, and Neovossia moliniae. 



