122 Transactions British Mycological Society. 
method of Schostakowitsch(16), a series of cultures was made 
in Petri dishes and exposed to illumination from one side only. 
A few strains showed a positive reaction to light, the conidio- 
phores bending towards the source of light. The strains showing 
this characteristic were S, 102D, 103B, 113, all of which were 
originally isolated from meat in cold storage. Several other 
strains isolated from similar sources showed no reaction to light. 
3. Influence of increased concentration of mineral salts. 
Schostakowitsch (16) states that he was able to distinguish the 
two forms Hormodendron and Cladosporium by their characters 
when grown in solutions containing a high concentration of 
potassium nitrate. A series of cultures of the two strains S and 
43 was made in a nutritive solution, to which various amounts 
of KNO, were added. Both strains grew in all strengths of 
KNO, up to saturation, and the differences between the two 
strains were much less in the more concentrated solutions than 
under more normal cultural conditions. 
IV. RELATION OF CLADOSPORIUM TO HORMODENDRON. 
According to Bancroft(z) conidia of the Cladosporium type 
when germinated at a low temperature (below 56° F.), form a 
mycelium which produces other conidia of the same type. If 
germinated at a higher temperature (60° F. or above) he states 
that the conidia formed belong to the Hormodendron type. In 
the course of the present work it was found that Bancroft’s 
statements could not be confirmed for any of the strains used. 
The “ Hormodendron” stage was produced in every culture 
grown at low as well as at high temperatures on both solid and 
liquid media. Even at — 6°C. “Black Spot” produced by arti- 
ficial inoculation of meat gave rise to many Hormodendron 
spores, although the proportion of large spores of Cladosporium 
type was greater than at ordinary temperature. 
On examination of the present series of cultures it was found 
that the distinction between Cladosporium and “‘ Hormodendron”’ 
was merely a question of the amount and character of the 
budding of the first-formed conidia as described above, and that 
the two forms merged gradually one into the other. 
It is noteworthy that in nature the “ Hormodendron”’ type is 
less common than the Cladosporium. In our experience the 
strains isolated from the latter type do not differ more from 
those isolated from the former type, than they differ among 
themselves. Thus the claim of Schostakowitsch (16) that he was 
able to differentiate the two types by 
(a) the positive heliotropism of Hormodendron, 
