Eriksson —On the vegetative life of some Uredineae. 57 
most part in Flemming’s Fluid, but sometimes in Hermann’s Fluid, in 
Absolute Alcohol, in Corney’s Fluid or in Merkel’s. The washing, ‘Ithe 
hardening and the paraffin-embedding were done in the usual way. The 
staining took place mostly with Flemming’s Saffranin-gentian-violet- 
orange, but now and then with Heidenhain’s Iron-alun-haematoxylin or 
with F uchsin-methyl- green. 
II. Perennial Mycelium. Does it exist in the 
wintering Corn-plant? 
The first pressing question which had to be solved was whether there 
exists in the wintering corn- plant (Winter Rye, Winter Wheat) a mycelium 
surviving from the late autumn of the one year until summer of the following 
year, at which time the new rust-pustules are breaking out. 
To explain this I fixed and embedded species of the leaf of three Wheat- 
varieties (Horsford’s Pearl, Michigan Bronze, Squarehead), and one Rye- 
variety (Pirna Rye) in the year 1902 on October 6, 14, and 27, and 
in the year 1903 from the same plots on April 28, May 28, June 5, 11, 
and 18, and lastly on July 4. From October 6, 1902 until June 18, 
1903 there was no trace of rust-pustules to be discovered on the plots. On 
July 4 we saw solitary spots of yellow rust-pustules ( Uredo glumarum ), 
breaking out on the wheat-leaves (Horsford’s Pearl), but the small pieces 
for embedding were taken as far away from these pustules as possible, on 
those parts of the leaves which looked wholly sound. The Rye leaves 
were clean also on July 4. 
From the embedded pieces of leaves very numerous series of sections 
were cut and examined. On this examination we have seen in none of the 
sections — and the research involved the examination of thousands of such — 
the least trace of mycelium either in the wheat or in the rye-leaves, not 
even in the wheat-sections (Horsford’s Pearl) of July 4, which were taken 
far from the pustules. 
From this examination we can conclude, I think, with a great degree 
of certainty, that the outbreak of Uredo glumarum on the wheat-leaves in 
the first days of July, and of Uredo dispersa one week later, could not be 
explained from a perennial mycelium in the corn-plant itself. Such a 
mycelium was not at all to be found there . 
I ought to observe that the period of the biennial corn-plant’s life, 
in which no mycelium is to be discovered, must be very varying in different 
years. For the season 1902-3 this period lasted from the sprouting in 
the beginning of October until the beginning of the following July, that 
is to say for nine months. In other seasons, when external conditions are 
favourable for the development of the Fungus, we can already see proleptic 
outbreaks of rust-pustules at the end of October or in November, and the 
