RUST FUNGI 193 



the teliospore reaches maturity, the nuclei fuse, and the uninucleate 

 condition then continues again until the formation of the aecia. In the 

 micro- and lepto-iorms, which have no aecium or uredinium, we find that 

 the association takes place at points in the ordinary mycelium, but 



Fig. 67. — Portion of a section of cedar apple about 5 mm. below a teliosorus. 

 Note (i) Binucleate intercellular inyceliiim; (2) the haustoria in various stages of 

 development; (3) the doubling of nucleoli in the nuclei of some of the parenchyma 

 cells of the host. Material collected on March 31. (After Reed. B. S., and CrabiU, 

 C. H., Techn. Bull. 9, Va. Agric. Exper. Slat., May. 1915.) 



always before the formation of the teUospores. Whether the 

 association of nuclei in the ordinary myceUum takes place by the 

 migration of a nucleus from one cell to another, or whether two daughter 

 nuclei become conjugate in one cell has not been settled definitely. 

 The pycnospores are probably abortive male cells. They have never 

 13 



