REED: SPECIALIZATION OF PARASITIC FUNGI 361 



been the first to suggest that the aecidial stage of the rust on Rhamniis 

 cathartica and Rh. Frangula belonged to two different groups of 

 gramineous hosts. This supposition was later confirmed by Eriksson 

 (34, 37, 42), Klebahn (77-81, 90) and Miihlethaler (loi, 102). These 

 same workers have further discovered the existence of races of the rust 

 on the groups of grasses which have their aecidial hosts on different 

 species of Rhammis. The specialization of Puccinia coronata Corda 

 has been found to be as follows : 



I. Specialized Races with their Aecidial Stage on Rhammis catharlica, Rh. 



utilis, Rh. dahurica, Rh. saxatilis and Rh. Imeretina (Puccinia coronifera Kleb.) 



1. Avenae on Avena sativa and A. brevis. 



2. Alopecuri on Alopecurus pralensis, A. arundinaceus and, to some extent, on 



Avena sativa. 



3. Festucae on Festiica ariindinacea, F. elatior, F. giganiea, F. varia and F. alpina. 



4. Lolii on Lolium remotum var. aristatum, L. perenne, L. rigidum, L. temulentum, 



L. italicum, Fesluca elatior and Holcus lanalus. 



5. Glyceriae on Glyceria aquaiica. 



6. Agropyri on Agropyron repens. 



7. Epigaei on Calamagrostis epigeios and to some extent on Avena sativa. 



8. Hold on Holcus lanattis and Lolium perenne. 



9. Bromi on Bromus erectus, B. erectus var. condensatus, B. inermis, B. secaliniis, B. 



sterilis, B. tectorum, B. commutatus and probably B. asper. 

 10. Arrhenatheri on Arrhenatherum elatius. 



II. Specialized Races with their Aecidial Stage on Rhamnus Frangula, Rh. 



Purshiana, Rh. Alaternus, Rh. californica and Rh. Imeretina 

 {Puccinia coronata (Corda) Kleb.) 



1. Calamagrostis on Calamagrostis arundinacea, C. lanceolata, C. phragmitoides, C. 



calybea and Phalaris arundinacea. 



2. Phalaridis on Phalaris arundinacea, Calamagrostis arundinacea and C. lanceolata. 



3. Agrostis on Agrostis vulgaris and A. stolonifera. 



4. Hold on Holcus lanatus and //. mollis. 



5. Agropyri on Agropyron repens. 



III. Race with its Aecidial Stage on Rhamnus alpina, Rh. pumila, Rh. Imeretina 



and Rh. Purshiana {Puccinia alpinae-coronata Miihlethaler) 



Calamagrostis on Calamagrostis varia and C. tenella. 



IV. Race with its Aecidial Stage on Rhamnus dahurica 

 {Puccinia himalensis (Barclay) Diet.) 



Brachypodii on Brachypodium silvaticum. 



V. Race whose Aecidial Stage is Unknown 

 Melicae on Melica nutans. 



