REVIEW OF FUNGOUS CLASSIFICATION 629 



Hemiascomycetes to Euascomycetes, caryogamy and meiosis are sepa- 

 rated in time and space into two steps of division ; caryogamy takes place 

 in special organs, the zeugites, while only meiosis is retained in the basidia 

 (Uredinales, pp. 562, 572 and 592; Ustilaginales, p. 599; Brachybasidia- 

 ceae, p. 433). While the zeugites undergo an increasingly richer develop- 

 ment, septate and develop to independent spore forms, in the basidia, 

 which only serve for meiosis, the basidial character becomes still weaker, 

 as happened in the endocaryogamous forms: the obsolete rust basidia 

 (type of Puccinia Malvacearum, p. 585) and the obsolete smut basidia 

 (p. 585) begin as metabasidia to die away in purely vegetative germina- 

 tions. In this manner, in the highest Basidiomycetes we descend again 

 to the starting point of the Phycomycetes (p. 610). 



