368 BROOKLYN BOTANIC GARDEN MEMOIRS 
4. Puccinia Magnusti Kleb.; uredo and teleuto stages on Carex acuti- 
formis and C. riparia; aecidial stage on Ribes alpinum, 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 WKleb. with the aecidial stage on 
Angelica silvestris and Carum carvt. 
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 WKleb. 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-amphibu. 
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. convolvulus and P. dumetorum. The aecidio- 
spores produced experimentally on the various species of Geranium, 
