396 



BROOKLYN BOTANIC GARDEN MEMOIRS 



In various heteroecious rusts it has been suggested that the aecidial 

 host may act as a bridge for races occurring on the uredo and teleuto 

 hosts to pass over on to other species normally beyond their range of 

 infection. In the case of Puccinia graminis the aecidial host, Berheris 

 vulgaris, is common to all the races specialized on different kinds of 

 grasses. In the aecidial stage the difference between the races on the 

 gramineous hosts might disappear and the aecidiospores produced on 

 the barberry might have a much wider range of infection. 



Several investigators have published data bearing on this point. 

 Eriksson (41) has infected the barberry using teleutospores from more 

 than fifty different grasses. In some of these cases the aecidiospores 

 produced were used to inoculate various gramineous hosts. Some of 

 Eriksson's results may be indicated in the following summary: 



Teleutospores from 



Aecidiospores Sown on 



AVENAE 



Avena sativa 



Briza maxima 



Bromu^ arvensis 



Bromus brachystachys 

 B ramus madritensis . . 

 Dactylis glomerata . . . 



Festiica myurus 



Festuca teytuiflora . . . . 



Koeleria setacea 



Milium effusum 



Phalaris cajiariensis . . 



Phleum asperum 



Vulpia bramoides . . . . 



Secalis 

 Agropyron repens. . . . 

 Bromus secalinus . . . . 



Elymus sibiricus 



Hordeum vulgar e 



Secale cereale 



AlRAE 



Aira boUnica 



POAE 



Poa caesia 



Poa compressa 



Tritici 

 Trilicum vulgar e 



2/2^5 



I /I 



I/I 

 I/I 

 I/I 

 I/I 

 I/I 

 I/I 

 I/I 

 2/2 



I/I 

 I/I 

 I/I 



O/I 



0/2 

 0/2 



O/I 



1/3 



O/I 

 O/I 



I/I 



? 5 S 



ik "^ 1"^ 



i/i 



O/I 



O/I 



I /I 



- ^ 5; - 



0/20/2 



o/i|i/i 



c/ijo/i 

 o/i i/i 



O/I 

 O/I 



O/I 



O/I 



I/I 



O/I 

 O/I 

 O/I 



I/I 



o/i o/i 

 o/i o/i 



I/I 



2/2 

 2/2 



O/I 



2/3 



I/I 

 I/I 

 I/I 



I/I 



2/2 



=^-^;' 



I/I 



O/I 



I/I 



O/I 



0/2 



O/I 

 O/I 

 O/I 



O/I 



O/I 

 O/I 

 O/I 

 O/I 

 O/I 

 O/I 

 O/I 



O/I 



1/2 



0/2 



O/I 



6/7 



In general, the aecidiospores from the barberry are restricted in 



^* The denominator of the fraction indicates the number of tests and the numer- 

 ator the number that were successful. 



