246 



INTRODUCTIOX TO THE STUDY OF FUNGI 



developed on Bcrhcris vul(/aris, Ijut no corresponding iiredo- 

 spores or teleutospores upon that plant, and therefore they 

 have to be sought elsewhere (Fig. 117). 

 On the other hand, the uredospores and 

 teleutospores of Puccinia graminis flourish 

 on wheat and other grasses, whilst no 

 spermogonia or aecidia have been known to 

 infest the latter plants. Hence it is con- 

 cluded that the above form the normal series, 

 with the spermogonia and aecidia on the 

 berberry, and the uredospores and teleuto- 

 spores on wheat, which completes the cycle. 

 This theory is supported by the contention 

 that the germinating spores of Aecidium 

 herheridis are capable of producing Puccinia 

 FiG.117.— AeLKiiospore graminis by artificial inoculation on wheat: 



in germiuation. Alter - , , i , . ■, 



Tuiasne. ^nd couvcrscly the promycehal spores of 



Puccinia graminis (Fig 118) may be used 

 to inoculate the leaves of the berberry, and produce thereon 

 Aecidium herheridis. This is the theory and its application, 

 which we will here leave as it 

 stands. In another group, the 

 Braclnj - 'pueciniae, spermogonia, 

 uredospores, and teleutospores are 

 found on the same species of plant, 

 but the aecidia are unknown. To 

 this succeeds the Hcmi-fuecinia , 

 in which uredospores and teleuto- 

 spores occur on the same plant, 

 but the spermogonia and aecidia 

 are unknown. It is here that the 

 sceptics w^ould place Puccinia 

 graminis were they not debarred p^^. ns— Puccinia teleutospore 



by the anathemas of the votaries germiuating and producing pro- 



of Heteroecism. Hereafter follows "^"''''^' '^°"'- ^"''" ^"'^^'^'• 

 the group Pucciniopsis, in which spermogonia, aecidia, and 

 teleutospores have been recognised, but not uredospores, so 

 that in this group of species the uredo stage is deficient. 

 Of the two remaining groups, Micro-pucciniae includes those 



