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over the surface of the blade and search for the stomata, as those of the latter 
spore-forms do. The last-named germ-tubes do veritably search for the stomata. 
The main tube almost always travels across the blade at right angles to its long 
axis, sending off, here and there, short rectangular branches when it passes over 
the junction of two cells, as is shown in figures in my previous paper.* Of course 
the minute germ-tube of the promycelium-spores is quite inadequate to do this. 
There is no reason, however, why these germ-tubes should not enter any part of 
the wheat plant that is not armour-plated. In the two experiments just men- 
tioned, in which wheat plants grown under glass were so placed that their 
plumules came in contact with the teleutospores of P. graminis, as soon as they 
came above ground, became infected with the fungus, while the control plant 
remained healthy. That this is by no means an impossibe suggestion is shown by 
the analogous case of Cystopus candidus, in which De Bary found the plants became 
infected with the fungus through the entrance of the zoospore germ-tubes into the 
cotyledons. But we are not confined to the plumule as the only vulnerable point; 
the rootlets may be points of entrance. Considering how constantly stray wheat 
plants growing upon manure heaps are affected with mildew, this mode of entrance 
does not seem at all improbable under those conditions. The roots and root-stock 
of the wheat plant are more likely tu be in contact with the germinating teleuto- 
spores than when the plant is grown in the ground. The fact, too, of perennial 
grasses being annually the hosts of various hetercecismal Puccini would also seem 
to indicate the possibility of the plants being infected through some other channel 
than the plumule. These points are, however, at present, only suggestions which 
T hope to put to the proof next spring. 
SOME OBSERVATIONS ON THE GERMINATION OF 
THE UREDINES. 
By Onarues B. Pirowricut, M.R.C.S.—Read October, 1881. 
WHILE conducting the experiments upon the hetercecism of Puccinia graminis and 
Aicidium berberidis, detailed in a recent number of ‘‘Grevillea,” my attention was 
drawn more or less directly to the various processes which take place during the 
development of these fungi. So interesting were these that I was induced to ex- 
tend my observations to other allied species, and during the summer a continuous 
series of observations were carried on. As a matter of course, the ground has 
already been gone over by many other mycologists, and the classical memoirs of 
M. Tulasne, which are in themselves well-nigh exhausted, leave but little margin 
for startling discoveries of unexpected novelties; yet so important is the subject 
in an economic point of view, and so interesting are many of the phenomena which 
* See fig. 1, 0; fig. 3, &. 
