156 Magnus . — On Aecidhim graveolens ( Shuttlew .). 
the cambium. As I had, however, looked for the mycelium 
in all the tissues of the stem, as is evident from my paper, 
‘ Ueber das Mycelium des Aecidium magellanicum , Berk 1 ,’ 
this criticism is of little weight. Eriksson in fact admits that 
I had investigated the cambium when he quotes my statement 
that I did not find the mycelium in it. He further states 
that while he had worked with living material, I had only 
examined specimens preserved in alcohol. I do not regard 
such an objection as a reasonable one ; nevertheless this year 
I have expressly used living material, and have obtained the 
same results. I have also extended my observations to 
ascertain how and where the mycelium develops in the 
branches of the witches’ brooms, how it arises in the buds, 
and how it develops in the leaves which, even in the bud, are 
covered with the fructification of the Fungus. 
For these observations I was able to use material rich in 
the fungus which was sent to me by Hofgartner Reuter from 
the Pfaueninsel near Potsdam, on April 24, 189 7, and by 
Herr J. A. Baumler, from Pressburg in Hungary, on May 8, 
1897. I owe my best thanks to these two gentlemen for this 
material. The latter was especially valuable to me, inasmuch 
as it consisted of a large number of young buds growing into 
elongated branches. 
Of course I was not able to decide, in response to Eriksson’s 
wish, whether this mycelium is derived from aecidiospores or 
from sporidia of germinated teleutospores. Up to the present 
time we do not know of any observations supporting the idea 
that such mycelia are different in any respect except in their 
extension in the host-plant. I have shown in earlier papers 
that the mycelium developed from the sporidia of the 
hibernated teleutospores often extends further into the tissue 
of the host-plant than that derived from the germinating 
uredospores or aecidiospores, which form in most cases a 
mycelium restricted to the region of infection (e. g. Puccinia 
Oreoselini , Strauss., and P. Cyani , Pass.) : but no other 
1 Berichte der Dent. Bot. Ges., Vol. xv, 1897. 
