6 $ 
F. E. Weiss. 
as such. The latter view would seem the more probable both by 
reason of the organic connection of the cell with the rootlet and 
from the similarity of its walls with those of the rootlet. If this 
should be the correct explanation, a fungus of the Urophlyctis type 
at once suggests itself as the probable cause both of the hyper¬ 
trophied cell and also of the development of a callus-like tissue. 
For most plants attacked by Urophlyctis are stimulated to pro¬ 
duce gall-like swellings in the formation of which active secondary 
growth of a similar kind to that seen in the Stigmarian root takes 
place. Here, however, the proliferation is internal probably owing 
to the almost hollow condition of the rootlet, just as is often the 
case in the Dandelion when attacked by Protoinyccs. 
Magnus has given us a very good account 1 of the parasitic fungi 
which attack the underground organs of plants and of all those 
enumerated and described by him the genus Urophlyctis seems 
to cause disturbances most like those seen in our rootlet. There are 
of course differences between the two. In the specimens described 
and figured by Magnus in the Annals of Botany- for example it will 
be seen that the hypertrophied cell, which contains the resting 
spores in the genus Urophlyctis, seems organically connected 
with the host plant throughout its whole extent, and does 
not therefore contract when its contents have escaped, but retains 
its oval shape. This and other differences might, however, be 
expected of a fungus which, however closely allied it may be to 
Urophlyctis, is so widely removed from it in point of time. 
The genus Urophlyctis is a parasitic fungus attacking the leaves 
and roots more particularly of marshy plants or of plants inhabiting 
regions which are flooded from time to time, and it would therefore 
seem quite reasonable to assume that the corresponding Palaeozoic 
genus Urophlyctites, represented so far by the species Oliveriauus, 
which infests the leaves of Alethopteris, might also be found to 
attack Stigmarian rootlets which we believe to have grown under 
conditions that must have been peculiarly favourable for this kind 
of fungus. If, as I think most probable, this was the case, and if 
the interpretation given above of the features observed in this 
Stigmarian rootlet should prove correct, I would suggest the 
name of Urophlyctites Stigniariae, for this problematical fungus. 
1 Abliaudlungen des Hot. Vereins der Provinz Brandenburg, 
xliv., 1902. 
2 Annals of Botany, Vol. xi., 1S97, p. 87. 
Owens College, Manchester. 
January 28th, 1901. 
