368 BROOKLYN BOTANIC GARDEN MEMOIRS 



4. Puccinia Magnusii Kleb. ; uredo and teleuto stages on Carex aciiti- 



formis and C. riparia; aecidial stage on Ribes alpiniim, R. 

 aureum, R. nigrum and R. sanguineum. 



5. Puccinia Ribis nigri-acutae Kleb.; uredo and teleuto stages on 



Carex acuta and C. stricta; aecidial stage on Ribes alpinum, R. 



aureum-, R. nigrum and R. sanguineum. 

 Puccinia Bistortae (Str.) DC. This rust has its uredo and teleuto 

 stages on species of Polygonum and its aecidial stage on various 

 umbellifers. It is broken up into distinct races based upon the choice 

 of the aecidial host. By some, these races are regarded as true species. 

 According to Klebahn (91) they are as follows: 



1. Puccinia Angelicae-Bistortae Kleb. with the aecidial stage on 



Angelica silvestris and Carum carvi. 



2. Puccinia Conopodii-Bistortae Kleb. with the aecidial stage on 



Conopodium denudatum. 

 Puccinia mammillata Schroet. This rust, also with its uredo and 

 teleuto stages on Polygonum, as a result of the work of Bubak (21) 

 and Semadeni (140), is separable into two races: 



1. Puccinia Angelicae-mammillata Kleb. with the aecidial stage on 



Angelica silvestris {Aecidium Bubakianum Juel). 



2. Puccinia Mei-mammillata Semadeni with the aecidial stage on 



Meum mutellina. 



Puccinia Polygoni-amphibii Pers. Several workers claim the 

 existence of at least two rusts on the various species of Polygonum 

 on the basis of minor morphological characteristics. Puccinia Poly- 

 goni-amphibii Pers. is recorded on Polygonum amphibium and P. 

 Polygoni-Convolvuli DC. on Polygonum convolvulus. P. and H. 

 Sydow (151) in their monograph of the rusts, however, claim that the 

 differences are not sufficient to distinguish the species and consequently 

 list the various Polygonums as hosts for the one rust, Puccinia Poly- 

 goni-amphibii. 



Tranzschel (152, 153) first demonstrated the heteroecism of this 

 Polygonum rust, connecting the uredo and teleuto stages on Polygonum 

 amphibium with the aecidial stage on Geranium palustre and G. 

 pratense. He further found that the uredo and teleuto stages on 

 Polygonum convolvulus was connected with the aecidial stage on 

 Geranium pusillum.. A number of other workers have confirmed the 

 connection between the uredo and teleuto stages on Polygonum and 

 the aecidial stage on Geranium. 



Jacob (66, 67) has carried out the most extensive series of cultural 

 experiments with the Polygonum rust, using teleutospores from Poly- 

 gonum amphibium, P. cotivolvidiis and P. dumetorum. The aecidio- 

 spores produced experimentally on the various species of Geranium, 



