REED: SPECIALIZATION OF PARASITIC FUNGI 361 
been the first to suggest that the aecidial stage of the rust on Rhamnus 
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 (101, 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 Rhamnus. The specialization of Puccinia coronata Corda 
has been found to be as follows: 
I, SPECIALIZED RACES WITH THEIR AECIDIAL STAGE ON Rhamnus catharlica, Rh. 
utilis, Rh. dahurica, Rh. saxatilis AND Rh. Imeretina (Puccinia coronifera Kleb.) 
1. Avenae on Avena sativa and A. brevis. 
2. Alopecurt on Alopecurus pratensis, A. arundinaceus and, to some extent, on 
Avena sativa. 
3. Festucae on Festuca arundinacea, F. elatior, F. gigantea, F. varia and F. alpina. 
4. Lolit on Lolium remotum var. aristatum, L. perenne, L. rigidum, L. temulentum, 
L. ttalicum, Festuca elatior and Holcus lanatus. 
5. Glyceriae on Glyceria aquatica. 
6. Agropyri on Agropyron repens. 
7. Epigaet on Calamagrostis epigeios and to some extent on Avena sativa. 
8. Holct on Hoicus lanatus and Lolium perenne. 
g. Bromi on Bromus erectus, B. erectus var. condensatus, B. inermis, B. secalinus, B. 
stertlis, B. tectorum, B. commutatus and probably B. asper. 
10. Arrhenatherit 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. 
. Phalaridis on Phalaris arundinacea, Calamagrostis arundinacea and C. lanceolata. 
. Agrostis on Agrostis vulgaris and A. stolonifera. 
. Holci on Hoicus lanatus and H. mollis. 
. Agropyri on Agropyron repens. 
nb wn 
III. Race WITH ITs AECIDIAL STAGE ON Rhamnus alpina, Rh. pumila, Rh. Imeretina 
AND Rh. Purshiana (Puccinia alpinae-coronata Mihlethaler) 
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. 
