Bailey.— Puccinia malvacearum and the Mycoplasm Theory. 177 
be inferred from an experiment conducted by Dandeno, 1 who scattered 
a large quantity of dead leaves and stems of mallows, which had been 
diseased the previous autumn, amongst patches of mallows which were just 
commencing to grow in the following spring. The infected litter produced 
no result. 
5. Absence of mycelium in seeds and young plants. Eriksson made 
numerous sections of both seeds and young plants, and failed in every case 
to find any trace of mycelium. 
Though it may be taken as an established fact that the fungus does not 
pass through the winter in a mycelial condition in the seed, there is evidence 
to suggest that in certain cases the mycelium persists in the stems and 
leaves of hollyhock or mallow plants growing in positions where they are 
sheltered by surrounding vegetation or litter. Taubenhaus 2 records a case 
in which he found living mycelium and even immature teleuto-sori through- 
out the winter and early spring in hollyhock leaves which had been mulched 
with horse manure. 
It may easily be imagined that the comparatively few spores which are 
needed to start the initial infection are derived chiefly from such* persistent 
mycelium, though a certain proportion of spores doubtless survive the 
winter and germinate direct in the following spring. 
6. Dimorphism in teleutospores. Eriksson found that teleutospores 
differed in the mode of their germination. Either a short thick septate 
promycelium is formed, which abstricts small pear-shaped sporidia from 
each of its segments, or a comparatively long thin promycelial tube may 
arise, which is marked by the fact that its base is frequently somewhat 
swollen and that it never produces sporidia. 
In this latter case the distal end of the tube divides up into three or 
four oblong segments which ultimately fall apart in a way which strongly 
recalls the formation of oidia in the Erysiphaceae. 
Taubenhaus also describes the formation of these * oidia and states 
that they subsequently germinate to form sporidia, which in turn germinate 
by the production of germ tubes. 
The present writer has been unable to confirm this last observation of 
Taubenhaus, but has frequently seen ‘oidia’ germinating direct by means of 
germ tubes. 
Eriksson lays very great stress on this dimorphism in promycelia, 
though he admits that the two forms of germination may sometimes be 
found in the same pustule. He states that spores taken in spring from 
pustules on plants which have been wintered over in greenhouses — and in 
which the fungus has consequently continued to live — germinate mostly 
1 Dandeno : Life-history of Puccinia malvacearum. Ninth Annual Report Mich. Acad. 
Sci., 1907. 
8 Loc. cit. 
N % 
