104 THE LOWER FUNGI— PHYCOMYCETES 



the host send their germ tubes into the interior and develop a 

 wide-spreading mycehum having no connection with the sporangia. 

 On this mycehum definite turbinate enhirgements are formed 

 (Fig. 37, t), which at maturity become septate, and from one of 

 the cells of each enlargement a thick-walled resting spore devel- 

 ops. The other cells remain attached for a time, and in the litera- 

 ture bear the name ^^ Sammelzellen.^' The mycelium is very 

 delicate, and soon disappears, the resting spores then lying free 



Fiu. 30.- — Urophlyclis alfalfae (Lagerheim) Magnus, causing galls at the crown 

 of an alfalfa plant. {After Jones and Drechsler 1920.) 



in the host cells and giving no indication of their origin. They 

 have been mistaken for the resting spores of Synchytrium, e.g., U. 

 -pluriannulatus (B. & C.) Farlow (1908: 12). The details of 

 resting spore formation are discussed by Clinton (1902: 56) for P. 

 maculare, by Tisdale (1919: 147) for P. zeae-maydis, and by 

 Jones and Drechsler (1920: 305) for U. alfalfae and V. pluri- 

 annulatus. From the latter account, especially it is evident that 

 the development of the mycelium and resting spores is a very 

 definite process. A comparison of the figures published by 



