REED: SPECIALIZATION OF PARASITIC FUNGI 375 



1. Uromyces Pastinacae-scirpi Kleb.; aecidial stage on Pastinaca 



sativa. 



2. Uromyces Berulae-scirpi Kleb.; aecidial stage on Berida angusti- 



folia. 



Dietel (28) was able to infect with teleutospores from a single host 

 Siitm latifoHum and Hippiiriis vulgaris. 



Gymnosporangium tremelloides Hartig. There is but little indi- 

 cation in the literature of the existence of specialized races in Gymno- 

 sporangium. Most of the species of this genus are quite restricted in 

 host range, often occurring on only a few species of a single genus of 

 host. Klebahn (89) gives some evidence for a host specialization of 

 Gymnosporangium tremelloides, the teleutospores of which are produced 

 on Juniperus communis. On the basis of cultural tests he suggests the 

 following: 



1. Gymnosporangium Ariae-tremelloides Kleb. Aecidial stage on 



Sorbus aria and 5. torminalis. 



2. Gymnosporangium Mali- tremelloides Kleb. Aecidial stage on Pyrtts 



nialus. 



Ochrospora Ariae (Fuckel.) Syd. Fischer (45) stated that he was 

 unable to infect Aruncus silvestris with uredospores of Ochrospora ariae 

 from Sorbus aucuparia. Tranzschel (152, 153), Fischer (45) and 

 Klebahn (89) showed that Sorbus aria, S. scandica and Pyrus mains 

 were all hosts of the same race, but Aruncus silvestris could not be 

 infected with spores from the same source. Later, however, Fischer 

 (48) was able to infect Sorbus aucuparia and Aruncus silvestris with 

 the same aecidiosporic material from Anemone nemorosa. 



Pucciniastrum Abieti-Chamaenerii Kleb. and P. Epilobii (Pers.) 

 Otth. These two rusts, according to Klebahn (83, 87), are dis- 

 tinguished almost solely on the basis of their life cycle. The former 

 is heteroecious with its aecidial stage on Abies balsamea and A. pectinata 

 and its uredo and teleuto stages on Epilobium angustifolium, E. 

 Dodonacum and E. latifolium. The latter has its uredo and teleuto 

 stages on a number of other species of Epilobium and its aecidial host 

 is as yet not known. 



Phragmidium disciflorum (Tode.) James. Bandi (15) suggests 

 that a host specialization occurs in this rust. He reports one race on 

 Rosa cinnamomea, R. pimpinellijolia and R. rubrifolia and a second 

 race on R. canina and R. centifolia. 



Coleosporium Campanulae (Pers.) Lev. This rust has its aecidial 

 stage on Pinus montana, P. rigida and P. sylvestris, and its uredo and 

 teleuto stages on a considerable number of different species and general 

 of the Campanulaceae. Wagner (170) and Klebahn (87, 91) have 

 made extensive studies with reference to the specialization of the rust 

 on different hosts. Klebahn makes the following races: 



