384 Philip: The Uredinee. 
Having thus far surveyed the history of the progress made 
in the study of Uredines, we may pause to consider what has 
been gained before proceeding to the investigation of problems. 
for which answers are at present to seek. One of our greatest 
living authorities considers the Uredines as occupying a medium 
stage of development between the ascomycetes and the basidio- 
mycetes. If this is so, then it seems probable that its parasitic 
habit has led toa degradation of type, as in many respects the 
Uredines approach the lower vegetable organisms, and certainly 
seem to have little in common with the more highly organised 
basidiomycetes. There has been a tendency among botanists 
to treat the fungi as the residual rubbish-heap of the vegetable 
kingdom, on to which everything may be thrown that does 
not find ready classification elsewhere. But, like the old order 
of infusoria, which, at one time, contained such diverse members 
as diatoms, oscillatoria, rotifers, and water bears, it will pro- 
bably be split up ; already the myxomycetes are semi-detached 
and the Uredines seem lhkely to follow. The Uredines consist 
primarily of a net-work of colourless threads whose office it is 
to permeate the internal vessels of the host plant and draw 
from them its nefarious parasitic means of existence. The 
dissemination of the spores follows the same lines as that of 
the’ pollen grains in the higher plants; the wind being the 
main agent, though insgcts, and even snails, which are very 
fond of the taste of the Uredines, have their share in the business. 
We must note here that all spores that are carried to, or 
fall on, any other plant than their regular host, do not ger- 
minate, or, if they do, fail to survive. Why? This is one of 
the problems we have to solve. Mycologists have deliberately 
tried to produce such infection, but in vain. 
Some species are only known to produce ecidiospores, others 
only uredospores, others again only teleutospores ; while others 
have ecidiospores and teleutospores; or uredospores and 
teleutospores ; in fact, there is every possible variation of 
the three forms. In many cases, however, this merely indicates 
the limits of our present knowledge, and it is quite possible 
that many of the missing links may yet be discovered upon 
other hosts, as in fact has been done in some species. 
Again, it would appear that some Uredines are able to main- 
tain continued existence without necessarily going through 
all the mutations which they might under more favourable 
circumstances undergo. Thus I have recently found consider- 
able quantities of the Puccinia on Polygonum amphibium, 
which, according to Plowright, has only uredo and teleutospores. 
but Dr. Tranzschel has found in Germany that it is associated 
with an Aicidium on Geranium pratense. Now Geranium 
pratense is a common plant in the marshy country between 
the Wolds and the river Derwent, and on August Bank Holiday 
Naturalist, 
