126 



Puccinia Gramineae. 



Subsequent research showed that there were still other species on the 

 same host-plant. Plowright separated a third species in 1888, mainly based 

 upon the fact that the aeeidiospores were only produced upon Rumex acetosa 

 and not upon other plants. Next, Ludwig in 1892 distinguished another 

 new rust on material sent from South Australia, viz., P. tepperi. Finally, 

 Arthur in 1902 published another new species which he named P. simillima 

 because it was very similar to P. magnusiana. 



There are thus at least five different species of Puccinia recorded upon 

 Phragmites communis, and it is not always easy to differentiate them, at 

 least by morphological characters. In three of them the aeeidiospores were 

 proved to occur on different host-plants by a series of cultures, and this is 

 considered by many a sufficient specific distinction. On these grounds they 

 would be considered biological species as in the case of Puccinias on various 

 cereals and grasses, but at the same time an attempt will be made here to 

 show any points in which they differ morphologically. Only two of the five 

 have hitherto been found in Australia, viz., P. magnusiana and P. tepperiy. 

 for although Dr. Cooke gives P. phragmitis in his Handbook of Australian 

 Fungi, it was probably intended for P. magnusiana, which has been found 

 in Victoria and South Australia. 



The life-history of this fungus was first determined by Dr. Plowright, 5 

 who found that the promycelial spores produced aecidia on Ranunculus, 

 repens and R. bulbosa, and conversely the aeeidiospores produced uredo- 

 spores and teleutospores on Phragmites. This was afterwards confirmed by 

 Fischer 1 and Klebahn. 1 



The five species may be arranged according to their aecidial hosts whei 

 known, as in the following table with their special characteristics shown :- 



It will be seen from the above that there are two types clearly 

 distinguishable morphologically, paraphysate and aparaphysate, and withi: 

 these limits there are only " biological species " based upon a difference - 

 aecidial host. 



If we compare P. trailii with P. phragmitis, tho teleutospores differ * 

 having a granular spore-membrane, and shorter and stouter pedicels. If 

 similar comparison is made of P. tepperi, the length of the pedicel is the 

 striking feature, and it is, perhaps, rather premature to separate it from 

 P. phragmitis until a distinct aecidial host has been proved. 



According to Arthur, P. simillima is distinguished from P. magnusiana 

 in the slender pointed teleutospores, the more clavate and less roughened 

 uredospores and the probably different aecidial host, viz., Anem ( 

 dichotoma L 



(Plate II., Fig. 18.) 



