192 



MORPHOLOGY. 



407a, Teleutcspores the last stage of the fungus in the season. — The teleu- 



tospores are dcvclopcii late in the seasuii, or late in the development of the 



host plant (in this case the 

 wheat is the host). They 

 then rest during the winter. 

 In the spring under favor- 

 able conditions each cell of 

 the teleutospore germi- 

 nates, producing a short 

 n"i\'celium called a p7'omy- 

 ct'liiim, as shown in figs. 

 222, 223. This promy- 

 celium is usually divided 

 into four cells. From each 

 cell a short, pointed pro- 

 cess is formed called a 

 " stt'?'ig/?ia.'" Through this 

 the pnjtoplasm moves and 

 forms a small gonidium on 

 the end, sometimes called 

 a sporidmm. 

 408. How the fungus gets from the wheat back to the barberry. — If these 



sporiilia from the teleuto-spores are carried by the wind so that they lodge on 



Germinating uredospnre ' 

 wheat rust. (After Warshal 

 Ward.l 



V\^. 22 1. 



Gerrn tube entering the 

 :af tliruugh a stoma. 



Fii^j. 222. 

 rcluutiispoiii g i: r m i 

 Ihi^, Ini riling promy- 



F 



igb. 



!-'4. 



FiK'. 2 3,. 



Protiiyceliiim of p;er- 

 niinatiiig tLlcvitosp .le 

 forming sporidia. 

 Puccinia gramini> w ! i -1 -' 



Germinating sporidia entering leal 

 Lil barberiy by myccliiini. 



1 Ater Marshall-Ward.) 



