REED: SPECIALIZATIOxN OF PARASITIC FUNGI 373 



4. Aecidial stage on Ranunculus silvaticus (Uromyces silvatici-dactylidis 



Krieg.). 



5. Aecidial stage on Ranunculus acer and R. polyanthemos. 



Juel (73) distinguishes several forms in Uromyces Poae: 



1 . Ficariae-nemoralis on Ranunculus Ficaria and Poa nemoralis. 



2. Ficariae-trivialis on Ranunculus Ficaria and Poa nemoralis and 



P. palusfris. 



3. Ficariae-pratensis on Ranunculus Ficaria and Poa pratensis. 



4. Repentis-nemoralis on Ranunculus repens and R. hulbosiis and Poa 



nemoralis. 



5. Repentis-trivialis on Ranunculus repens and Poa trivialis and P. 



awwwa. 



6. Auricomi-pratensis on Ra7iuncidus auricomus and Poa pratensis and 



P. nemoralis. 



7. Cassuhici-pratensis on Ranunculus cassuhicus and Poa pratensis. 



8. Repentis-pratensis on Ranunculus repens and Poa pratensis. 



9. Bullati-bulbosae on Ranunculus bullatus and Poa bulbosa. 

 Uromyces Fabae (Pers.) de Bary. Jordi (70, 71) has distinguished 



the following specialized races on this autoecious rust which is recorded 

 as occurring on species of Lathyrus, Lens, Pisum, and Vicia: 



1. On Lathyrus vermis and probably on Pisum sativum. 



2. On Ficia Pa&a and Pisum sativum. 



3. On Ficia cracca, V. hirsuta and Pisum sativum. 



It should be noted that Pisum sativum is listed as a host for all 

 three specialized races. 



Uromyces Geranii (DC.) Otth and Wartm., and U. Kabatianus 

 Bubak. The first mentioned species is reported as occurring on a 

 large number o£ different species of Geranium, while the second men- 

 tioned has been reported only on Geranium pyrenaicum. Bubak (23) 

 has called attention to minor morphological differences between the 

 two rusts. 



Bock (19) carried out tests with uredospores of Uromyces geranii 

 from Geranium silvaticum and was able to infect sixteen species while 

 thirteen gave negative results. Jacob (66, 67) also conducted experi- 

 ments with the rust, using teleutospores from Geranium silvaticum and 

 aecidiospores produced from the teleutosporic inoculation. A con- 

 siderable number of species of Geranium were successfully infected. 

 A few gave negative results. Jacob also used teleutospores of Uro- 

 myces Kabatianus from Geranium pyrenaicum and found that this 

 rust could also be transferred to a considerable number of other species 

 of Geranium. The host range of the two rusts is very similar and the 

 differences between the two depend upon minor structural differences 

 and not on host relations. 



