HEMIBASIDIOMYCETES 



323 



into a dense branched mycelium which eventually bears 

 secondary spores, either in the liquid or on branches that 

 rise into the air; or the mycelium continues to develop 

 like the sprouting fungi by gemmation or the production 

 of myriads of minute cells, which become detached as in 

 the yeasts or Saccharomycetes. 



De Bary considered the conjugation of secondary spores 



FlG. 89. Germinating spores of species of Ustilaginaceae. i, Ustilago 

 arundinellae ; 2, Tilletia decipiens, the secondary spores producing 

 tertiary spores ; 3, Tilletia zonata. (After Brefeld. ) All highly mag. 



as a sexual act, an idea not now entertained ; furthermore, 

 there is no evidence of sexualitv met with in the group. 



Two distinct types of structure are manifested in the 

 mode of germination of resting-spores. In the first, 

 illustrated by Ustilago^ the short promycelial tube is 

 divided into three or four cells by transverse septa, and 

 each cell gives origin to one or several secondary spores. 

 Those species having this type of structure are considered 



