HEMIBASIDIOMYCETES 



[CH. 



194 



pairs of associated nuclei takes place. Rawitscher observed a quite similar 



life-history in T. laevis. 



In the parasitic mycelium of Doassansia Alismatis and Entyloma Glancn 

 (fig. 162) Dangeard observed binucleate cells and the fusion of their nuclei 



Fi". 162. Development of brand-spores ; a. Doassansia Alismatis 

 (Nees) Corn.; b. Entyloma Glaucii Dang.; after Dangeard. 



in pairs in preparation for the formation of the brand-spores. The same 

 stages were recorded by Lutman \nDoassansiadeformans, Entyloma Nympheae 

 and Urocystis A nemones (fig. 163). 



Fig. 163. Urocystis Anemones (Pers.) Wint. ; mycelium and young spore 

 ball ; afiei Lutman. 



Tuburcinia primulicola infects various species of Primula and gives rise 

 to conidia as well as to brand-spores during its parasitic stage. Wilson 

 has shown that the conidia develop in the young flower on a mycelium 

 of uninucleate cells which apparently persists in the host plant throughout 

 the winter. When the flower opens the conidia conjugate in pairs, and a 

 nucleus passes through the connecting tube so that one conidium is empty 

 and the other binucleate. Germ-tubes with paired nuclei are later produced 

 and doubtless give rise to the mycelium of binucleate cells which bears the 

 brand-spores. This mycelium ramifies in the superficial tissue of the placenta 

 and between the ovules, giving rise to brand-spores in the same flowers in 

 which the conidia were previously developed. On the germination of the 



