178 Transactions British Mycological Society. 
Table I. Cultures on tomato agar were always used. 
Host or medium used Forms used Results 
(1) Sterilised tomato stems in AllexceptG, Very profuse growth of my- 
tubes S and U celium in all; fruiting 
bodies generally formed 
(2) Tomato plants; needle B,C,D,E,H, Only L took; canker en- 
pricks made in stem K2,LandT _ circled the stem which col- 
lapsed; pycnidia formed 
(3) Potato agar Allexcept G, Mycelium scanty. Fruiting 
S and U bodies usually formed spar- 
ingly 
(4) Melon plantsin greenhouse. 8, D, K2,L,T No infection 
Needle pricks made in stem 
(5) Cucumber plants in green- 56,L, T No infection 
house. Needle pricks made 
in stem 
(6) Carrots in the laboratory. A, B, D, J No infection 
Needle prick inoculations 
(7) Apples (Cox’s Orange) in 8B, J,L No infection 
the laboratory. Needle prick 
inoculations 
(8) Potatoes in the laboratory. C, E, J, L L formed a dry sunken 
Needle prick inoculations canker with typical pyc- 
nidia and spores. C, £, J 
without effect 
(9) Sterilised potato cores Allexcept G, Generally a profuse growth 
S and U of mycelium with a fair 
number of fruiting bodies 
(10) Green grapes kept in an AllexceptG No infection 
incubator at 27°C. Needle and S 
prick inoculations 
(11) Dox’s medium (5)(30grms. All except G, Mycelium generally profuse 
cane sugar per litre) S and U and dark coloured, quite 
obscuring the fruit bodies 
(12) Dox’s medium (15 grms. AllexceptG Mycelium less _ profuse, 
cane sugar per litre) lighter colour, fruiting 
bodies plentiful 
(13) Dox’s medium (7-5 grms. AllexceptG Mycelium less profuse, fruit- 
cane sugar per litre) ing bodies plentiful 
(14) Green tomato fruitsinthe AllexceptG All formed typical rots 
laboratory. Needle prick in- and S except U 
oculations 
In the course of these experiments it was soon found that 
these forms of fungi took on great differences in growth-charac- 
teristics according to the medium used; with the exception of 
type C it was impossible to pick out these forms by any feature 
which was constant throughout all the media and hosts tried. 
The conclusion was reached that it was absolutely necessary 
to use a purely artificial medium like Dox’s, if any attempt 
was to be made to put on record differences between such 
closely related species or varieties as were being used, which 
would have value for other workers. 
