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RECENT OBSERVATIONS OF PROFESSOR ERIKSSON ON T 
RUSTS OF OUR CEREALS, 
By C. B. PLowricut, M.D. 
Since 1890. Professor Eriksson has been working experimentally o 
the life-history of the fungi which cause the various rusts of our cere 
crops. In July of last year he delivered a lecture at Stockholm to th 
Scandinavian Congress of Agriculturists, in which he epitomised his 
nine years’ work. In 1894 he, in association with Dr. Ernest Henning, 
published that large volume, Die Getreideroste, in which the autho 
showed that the mildew of Wheat meant a great deal more tha 
simply Puccinia graminis with its ecidiospores on the Barberr 
Continued observations have confirmed and amplified the results the 
obtained. Prior to the appearance of this work the cereal rusts we 
regarded as being due to three Pucciniz, viz.—P. graminis P. with 
zecidiospores on Barberry; P. rubigo-vera D. C., with its acidiospor 
on Anchusa; P. coronata Corda, with its zcidiospores on Rhamnus. 
The authors found that P. graminis was divisible into two species— 
(1) the true P. graminis, with its ecidiospores on Barberry ; (2) 
Phlei-pratensis E. & H., which occurs on P. pratense, and Festu 
elatior with unknown zcidiospores. But more than this, they fou 
that P. graminis occurs in six biologically distinct forms on Rye, Oat, 
Wheat, Aira, Agrostis, and Poa, which they call Forma Secalis, 
Avene, Tritici, Aire, Agrostidis, and Poze. Now these specialized 
forms, or varieties or sub-species, call them what you like, have thi 
in common—-that they all have their zcidiospores upon the Barberry 
but the zcidiospores formed, let us say, from Forma Secalis on Rye 
will not, when placed on Oat, or Wheat, or Poa, or Aira, or Agrostis 
give rise to the uredo, but when placed on Rye they will do so. No 
will the uredospores from Rye give rise to the uredo on any of th 
above-named grasses. Let us go a little further: there is a cert 
group of grasses to which Forma Secalis is confined, this includes not | 
only Rye, but also Barley, “I'witch, Elymus arenarius, and Bromu 
secalinus, and to these (with one or two closely allied species, 4g 
Hordeum jubatum, Triticum caninum and desertorum), it is confined 
The next form, Avene, is confined to the Oat, Avena elatior, sterill 
Dactylis glomerata, Alopecurus pratensis, Milium effusum, Lamarck 
aurea, and Triosteum distichophyllum. 

