518 BOTANICAL GAZETTE — [JUNE 
stration of the connection between the crown rusts of grasses and the aecidia 
occurring on species of Rkamnus, these rusts have been more especially investi- 
gated by Ertksson and by KLEBABN, with the result that two species have been 
differentiated: Puccinia coronata (Corda) Kleb. with aecidia chiefly on Rham- 
nus Frangula; and P. coronifera Kleb. with aecidia chiefly on R. cathartica. 
These comprise several form-species whose teleutospore generation in each 
case is confined to a small group of grasses. To these collective species MUHLE- 
THALER? has added a third, described as P. alpinae-coronata with aecidia on 
Rhamnus alpina and R. pumila. 
The cultural work, which covers an unusually large number of infection 
experiments, emphasizes more strongly the facts already suggested in the work 
of KLEBAHN and of Eriksson, that the crown rusts are not so strictly limited, 
in their specialization, to certain hosts as some of the earlier experiments would 
seem to indicate, and that some of the form-species formerly established should 
not be kept separate. Thus, for example, the form occurring on the members 
of the genus Lolium can be transferred to members of the genus Festuca, show- 
ing that a sharp separation of f.sp. Loli and f.sp. Festucae is impossible. There 
is also evidence to show that the degree of specialization of different forms is not 
the same in different regions, a fact which JaczEwskr” has already pointed out 
in his studies on Russian grain rusts. Unfortunately, the present experiments 
were not continued long enough to bring out all the interrelationships of the 
different form-species. The cultures reported comprised (1) infection of grasses 
either directly by aecidiospores, or indirectly by uredospores derived from the 
aecidiospore infection; and (2) infection of members of the genus Rhamnus by 
teleutospores from these grasses. The aecidial material was mostly gathered 
in its native habitat, so that there could be no assurance of its purity, and 
the experiments were not continued long enough to isolate with certainty the 
different form-species whose aecidia occur on the same species of Rhamnus. 
For these reasons, no attempt is made in this review to distinguish between the 
different form-species. For experimental evidence bearing on this point the 
original paper must be consulted. 
Aecidiospores from Rhamnus Frangula, or the uredospores derived from 
these, infected Phalaris arundinacea, Calamagrostis arundinacea, Glyceria 
fluitans, and Anthoxanthum ordoratum (doubtful). Teleutospores (sporidia) 
from Phalaris arundinacea infected Rhamnus Frangula, R. Purshiana, R. 
californica, E. imeretina (spermagonia), and R. alaternus (spermagonia). 
Aecidiospores from Rhamnus cathartica, or the resulting uredospores, 
infected, in one series, Lolium perenne, L. rigidum, L. italcum, L. temulentum, 
L. remotum var. aristatum, Festuca elatior, F. arundinacea, Phleum pratense 
(poorly), and Dactylis glomerata (poorly). The teleutospores from Lolium 
9 MtuLetHater, F., Infektionsversuche mit Rhamnus befallenden Kronenrosten. 
Centralbl. Bakt. II. 30: 386-419. 1911. 
t Rev. Bot. GAz. 51:75. IgII. 
