BASIDIOMYCETES 



435 



at once gains access to the nutritive cells. In about a fortnight the 

 infected spot will be producing fresh uredospores. 



The teleutospores may arise from the same spot as the uredospores, 



Fig. 332. 



Germinating uredospores, showing various stages of development of the germ- 

 tubes, a, b, c. Very highly magnified. (After Marshall Ward.) 



but later in the season. They differ from them in being closely packed 

 and firmly attached, as well as in structure. Each spore is spindle- 

 shaped, and is partitioned into two cells, each with a dark brown coat 

 (Fig. 334)- Like other cells of the mycelium and the uredospores 



Fig. 333- 

 Longitudinal section of a leaf of Wheat, showing a germ-tube from a uredospore 

 passing through a stoma (a) into the intercellular space (b). Very highly magnified. 

 (After Marshall Ward.) 



themselves, each cell contains two nuclei. They do not germinate till 

 the following spring. In March or April, after a few hours in water, each 

 cell puts out a delicate tube (Fig. 335). This, after segmenting to form 

 four distal cells, constitutes what has been called the promyceliutn, 



